A Question regarding arguments against the Nicene Creed

Warden's thesis is not strange at all. That is what the word was used for in a several ancient Greek texts:

μονο-γενής, ές, Ep. and Ion. μουνο-, (γένος): the only member of a kin or kind: hence, generally, only, single. Used as such in Hes.Op.376, Hdt.7.221, cf. Ev.Jo.1.14, Ant.Lib.32.1; of Hecate, Hes. Th.426.

The association with "begotten" is logical for a Latin speaker, as the Greek γενής shares the same IndoGermanic root as the Latin verb genere, which can both mean to be born and to beget.

(used nine times in scripture)

OP makes the oft repeated mistake of only counting the NT as Greek when there are other Greek scriptures. When the LXX is taken into account 'μονογενης' in its various forms appears 20 times. (Although, this runs afoul of the slippery definition of the word 'scripture' because it includes 7 citations in the Apocrypha.)

If we are to adhere to Sola Scriptura, at its broadest extent, then the Nicene viewpoint just edges out the Warden interpretation. However, 3 times as many verses either are ambiguous enough to allow either viewpoint or does not support either -- and at worse entirely offers another view altogether at least 3 times. If you take out the Apocryphal verses, then the Nicene view loses more than half of its explicit supporting verses. This brings its edging out Warden's view down to winning out by just one more verse.

For your review, here are the verses:

μονογενεῖς Noun, Acc Plur Masc

1. Tobit 8:17

• εὐλογητὸς εἶ ὅτι ἠλέησας δύο μονογενεῖς· ποίησον αὐτοῖς, δέσποτα, ἔλεος, συντέλεσον τὴν ζωὴν αὐτῶν ἐν ὑγιείᾳ μετὰ εὐφροσύνης καὶ ἐλέους.
• (NRSV) Blessed are You because You had compassion on two only children. Be merciful to them, O Master, and keep them safe; bring their lives to fulfillment in happiness and mercy.”
• [Tobit’s son Tobias and his wife Sarah are both called the only child of their respective parents – a similar use in common with the Nicene, although ambiguous here, other verses in Tobit make this explicit.]

μονογενές Adj, Nom/Acc Sing Neut

1. WisSol 7:22

• Ἔστιν γὰρ ἐν αὐτῇ πνεῦμα νοερόν, ἅγιον, μονογενές, πολυμερές, λεπτόν, εὐκίνητον, τρανόν, ἀμόλυντον, σαφές, ἀπήμαντον, φιλάγαθον, ὀξύ, ἀκώλυτον,
• (NRSV) There is in her a spirit that is intelligent, holy, unique, manifold, subtle, mobile, clear, unpolluted, distinct, invulnerable, loving the good, keen, irresistible,
• [Wisdom has an only-begotten spirit in her? A use counter to the Nicene.]

μονογενὴ/μονογενῆ Adj, Acc Sing Masc/Fem, Nom/Acc Plur Neut

1. Psa 22:20 (LXX: Psa 21:21)

• ῥῦσαι ἀπὸ ῥομφαίας τὴν ψυχήν μου καὶ ἐκ χειρὸς κυνὸς τὴν μονογενῆ μου·
• (RSV) Deliver my soul from the sword, my life from the power of the dog!
• (AMPC) Deliver my life from the sword, my dear life [my only one] from the power of the dog [the agent of execution].
• [Only-begotten life? Unique life? Or is the Psalmist alluding to an only child?]

2. Psa 35:17 (LXX: Psa 34:17)

• κύριε, πότε ἐπόψῃ; ἀποκατάστησον τὴν ψυχήν μου ἀπὸ τῆς κακουργίας αὐτῶν, ἀπὸ λεόντων τὴν μονογενῆ μου.
• (NRSV) How long, O Lord, will you look on? Rescue me from their ravages, my life from the lions!
• (AMPC) Lord, how long will You look on [without action]? Rescue my life from their destructions, my dear and only life from the lions!
• [Only-begotten life? Unique life? Or is the Psalmist alluding to an only child?]

3. Odes 15:13

• κύριε υἱὲ μονογενὴ
• Lord, the only-begotten Son
• [Follows orthodox pattern, since it is a song written by Nicenean adherents.]

4. PsSol 18:4

• ἡ παιδεία σου ἐφʼ ἡμᾶς ὡς υἱὸν πρωτότοκον μονογενῆ ἀποστρέψαι ψυχὴν εὐήκοον ἀπὸ ἀμαθίας ἐν ἀγνοίᾳ.
• (Brenton) Your discipline for us [is] as for a firstborn son, an only child, to divert the docile soul from the stupidity [caused] by ignorance.
• [Refers to God as disciplining Israelites as though they were His only-begotten child, i.e. a national, corporate only-begotten child. God has an only-begotten son besides Jesus? Or is this only metaphorical? Does this contrasts with the ‘unique’ interpretation?]

5. John 3:16

• Οὕτως γὰρ ἠγάπησεν ὁ Θεὸς τὸν κόσμον, ὥστε τὸν Υἱὸν τὸν μονογενῆ ἔδωκεν, ἵνα πᾶς ὁ πιστεύων εἰς αὐτὸν μὴ ἀπόληται ἀλλʼ ἔχῃ ζωὴν αἰώνιον.
• (NRSV) For God so loved the world that he gave his only Son, so that everyone who believes in him may not perish but may have eternal life.
• [Ambiguous – fits either intpretation.]

6. Heb 11:17

• Πίστει προσενήνοχεν Ἀβραὰμ τὸν Ἰσαὰκ πειραζόμενος, καὶ τὸν μονογενῆ προσέφερεν ὁ τὰς ἐπαγγελίας ἀναδεξάμενος,
• By faith Abraham, when put to the test, offered up Isaac. He who had received the promises was ready to offer up his only son,
• [So, Abraam had only one child? No, Ishmael and not so many sons had Father Abraham? So, I’m not one of them and nor are you?]

7. 1Jo 4:9

• ἐν τούτῳ ἐφανερώθη ἡ ἀγάπη τοῦ Θεοῦ ἐν ἡμῖν, ὅτι τὸν Υἱὸν αὐτοῦ τὸν μονογενῆ ἀπέσταλκεν ὁ Θεὸς εἰς τὸν κόσμον ἵνα ζήσωμεν διʼ αὐτοῦ.
• God’s love was revealed among us in this way: God sent his only Son into the world so that we might live through him.
• [Ambiguous – fits either intpretation.]

μονογενής/μονογενὴς

1. Judg 11:34

• Καὶ ἦλθεν Ιεφθαε εἰς Μασσηφα εἰς τὸν οἶκον αὐτοῦ, καὶ ἰδοὺ ἡ θυγάτηρ αὐτοῦ ἐξεπορεύετο εἰς ἀπάντησιν αὐτοῦ ἐν τυμπάνοις καὶ χοροῖς· καὶ αὕτη μονογενὴς αὐτῷ ἀγαπητή, καὶ οὐκ ἔστιν αὐτῷ πλὴν αὐτῆς υἱὸς ἢ θυγάτηρ.
• (NRSV) Then Jephthah came to his home at Mizpah; and there was his daughter coming out to meet him with timbrels and with dancing. She was his only child; he had no son or daughter except her.
• [Used in a similar context as the Nicene formula and adds explicitness in a following phrase.]

2. Tobit 3:15

• καὶ οὐκ ἐμόλυνα τὸ ὄνομά μου οὐδὲ τὸ ὄνομα τοῦ πατρός μου ἐν τῇ γῇ τῆς αἰχμαλωσίας μου. μονογενής εἰμι τῷ πατρί μου, καὶ οὐχ ὑπάρχει αὐτῷ παιδίον, ὃ κληρονομήσει αὐτόν, οὐδὲ ἀδελφὸς ἐγγὺς οὐδὲ ὑπάρχων αὐτῷ υἱός, ἵνα συντηρήσω ἐμαυτὴν αὐτῷ γυναῖκα. ἤδη ἀπώλοντό μοι ἑπτά· ἵνα τί μοι ζῆν; καὶ εἰ μὴ δοκεῖ σοι ἀποκτεῖναί με, ἐπίταξον ἐπιβλέψαι ἐπʼ ἐμὲ καὶ ἐλεῆσαί με καὶ μηκέτι ἀκοῦσαί με ὀνειδισμόν.
• (NRSV) and that I have not disgraced my name or the name of my father in the land of my exile. I am my father’s only child; he has no other child to be his heir; and he has no close relative or other kindred for whom I should keep myself as wife. Already seven husbands of mine have died. Why should I still live? But if it is not pleasing to you, O Lord, to take my life, hear me in my disgrace
• [Used in a similar context as the Nicene formula and adds explicitness in a following phrase.]

3. Tobit 6:11 (AlexVat)

• εἶπεν ὁ ἄγγελος τῷ παιδαρίῳ Ἄδελφε, σήμερον αὐλισθησόμεθα παρὰ Ραγουηλ, καὶ αὐτὸς συγγενής σού ἐστιν, καὶ ἔστιν αὐτῷ θυγάτηρ μονογενὴς ὀνόματι Σαρρα·
• (NRSV) Raphael said to the young man, “Brother Tobias.” “Here I am,” he answered. Then Raphael[a] said to him, “We must stay this night in the home of Raguel. He is your relative, and he has a daughter named Sarah.
• [The only-begotten or uniqueness is almost ignored in translation.]

4. Tobit 6:15 (Sin)

• καὶ νῦν φοβοῦμαι ἐγώ – ὅτι αὐτὴν οὐκ ἀδικεῖ, ἀλλʼ ὃς ἂν θελήσῃ ἐγγίσαι αὐτῆς, ἀποκτέννει αὐτόν· μονογενής εἰμι τῷ πατρί μου – μὴ ἀποθάνω καὶ κατάξω τὴν ζωὴν τοῦ πατρός μου καὶ τῆς μητρός μου μετʼ ὀδύνης ἐπʼ ἐμοὶ εἰς τὸν τάφον αὐτῶν· καὶ υἱὸς ἕτερος οὐχ ὑπάρχει αὐτοῖς, ἵνα θάψῃ αὐτούς.
• (NRSV) It does not harm her, but it kills anyone who desires to approach her. So now, since I am the only son my father has, I am afraid that I may die and bring my father’s and mother’s life down to their grave, grieving for me—and they have no other son to bury them.
• [Used in a similar context as the Nicene formula and adds explicitness in a following clause – although, the word ‘son’ is not present in the Greek and must be inferred.]

5. Psa 25:16 (LXX: Psa 24:16)

• ἐπίβλεψον ἐπʼ ἐμὲ καὶ ἐλέησόν με, ὅτι μονογενὴς καὶ πτωχός εἰμι ἐγώ.
• (NRSV) Turn to me and be gracious to me, for I am lonely and afflicted.
• [The translation adds another view to the mix. Not unique nor only-begotten, but solitary.]

6. Luke 7:12

• ὡς δὲ ἤγγισεν τῇ πύλῃ τῆς πόλεως, καὶ ἰδοὺ ἐξεκομίζετο τεθνηκὼς μονογενὴς υἱὸς τῇ μητρὶ αὐτοῦ, καὶ αὐτὴ ἦν χήρα, καὶ ὄχλος τῆς πόλεως ἱκανὸς ἦν σὺν αὐτῇ.
• (NRSV) As he approached the gate of the town, a man who had died was being carried out. He was his mother’s only son, and she was a widow; and with her was a large crowd from the town.
• [Ambiguous – fits either interpretation.]

7. Luke 8:42

• ὅτι θυγάτηρ μονογενὴς ἦν αὐτῷ ὡς ἐτῶν δώδεκα καὶ αὐτὴ ἀπέθνῃσκεν. Ἐν δὲ τῷ ὑπάγειν αὐτὸν οἱ ὄχλοι συνέπνιγον αὐτόν.
• (NRSV) for he had an only daughter, about twelve years old, who was dying. As he went, the crowds pressed in on him.
• [Ambiguous – fits either interpretation.]

8. Luke 9:38

• καὶ ἰδοὺ ἀνὴρ ἀπὸ τοῦ ὄχλου ἐβόησεν λέγων Διδάσκαλε, δέομαί σου ἐπιβλέψαι ἐπὶ τὸν υἱόν μου, ὅτι μονογενής μοί ἐστιν,
• (NRSV) Just then a man from the crowd shouted, “Teacher, I beg you to look at my son; he is my only child.
• [Ambiguous – fits either interpretation.]

9. John 1:18

• Θεὸν οὐδεὶς ἑώρακεν πώποτε· μονογενὴς Θεὸς ὁ ὢν εἰς τὸν κόλπον τοῦ Πατρὸς, ἐκεῖνος ἐξηγήσατο.
• (ESV) No one has ever seen God; the only God, who is at the Father's side, he has made him known.
• [The only-begotten God? Here we have either polytheism or Arianism – definitely not what Nicaea tried to establish. (Or we could just explain it away to the detriment of God preserving His Holy Word through the centuries.)]

μονογενοῦς Adj, Gen Sing Masc/Fem/Neut

1. John 1:14

• Καὶ ὁ Λόγος σὰρξ ἐγένετο καὶ ἐσκήνωσεν ἐν ἡμῖν, καὶ ἐθεασάμεθα τὴν δόξαν αὐτοῦ, δόξαν ὡς μονογενοῦς παρὰ Πατρός, πλήρης χάριτος καὶ ἀληθείας.
• (NRSV) And the Word became flesh and lived among us, and we have seen his glory, the glory as of a father’s only son, full of grace and truth.
• [Ambiguous, could fit either party’s argument., but the word ‘son’ must be inferred as it is not present in the Greek.]

2. John 3:18

• ὁ πιστεύων εἰς αὐτὸν οὐ κρίνεται· ὁ μὴ πιστεύων ἤδη κέκριται, ὅτι μὴ πεπίστευκεν εἰς τὸ ὄνομα τοῦ μονογενοῦς Υἱοῦ τοῦ Θεοῦ.
• Those who believe in him are not condemned; but those who do not believe are condemned already, because they have not believed in the name of the only Son of God.
• [Ambiguous, could fit either party’s argument.]