Are 'Nestorians' still considered heretics?

Yes, it is still a heresy to think there be two distinct persons in the Incarnate Christ (cf. Fr. Hardon, Catholic Dictionary, "Nestorianism").

The Council of Ephesus (431) defined this dogma against Nestorius (Denzinger 111a):

For we do not say that the nature of the Word was changed and made flesh, nor yet that it was changed into the whole man (composed) of soul and body but rather (we say) that the Word, in an ineffable and inconceivable manner, having hypostatically united to Himself flesh animated by a rational soul, became Man and was called the Son of Man, not according to the will alone or by the assumption of a person alone, and that the different natures were brought together in a real union, but that out of both in one Christ and Son, not because the distinction of natures was destroyed by the union, but rather because the divine nature and the human nature formed one Lord and Christ and Son for us, through a marvelous and mystical concurrence in unity. … For it was no ordinary man who was first born of the Holy Virgin and upon whom the Word afterwards descended; but being united from the womb itself He is said to have undergone flesh birth, claiming as His own the birth of His own flesh. Thus [the holy Fathers] did not hesitate to speak of the holy Virgin as the Mother of God.

Institutional Catholicism no longer denounces Nestorians as heretics, concentrating instead on ecumenical dialog, as the document mentioned in the OP shows. In some cases the Church even allows intercommunion with Nestorians. However, the doctrine itself is still considered heterodox. Regarding the Church of the East, it rejects the label "Nestorian," pointing out:

The current Christological terminology comes from old Greek philosophical terms or is a result of theological controversies, or abstract expressions. Today our people cannot understand them; therefore, we need to look for new understandable words to abide by.

Even the Protestant tradition of refusing to venerate Mary as the Theotokos [Mother of God] has been denounced as semi-Nestorian heresy by both Orthodox and Catholic sources alike. However, with the advent of Protestantism and the later Ecumenical movement, the definition of heresy is not nearly as clear as it once was. Especially since Vatican II, the Church has moved away from denouncing "heretics" as such.

Formally, Nestorianism as a doctrine is still considered heretical by Catholics, Orthodox and many Nicene-based Protestants. However the emphasis among institutional churches recently has been to concentrate on what unites Christians, rather than what divides them. The Nestorian tradition, variously defined, has a major presence in the Middle East, Iran, China and India. Some of these churches, are, in fact in communion with the Pope. In that sense, they are no longer considered heretics, or at least their heterodox teachings no longer disqualify them from inter-communion.

In 1994 the Catholic Church issued an official document providing guidelines of relations between Catholics and the [Nestorian] Assyrian Church of the East. While acknowledging differences, the document emphasizes that the two churches have taken:

...a basic step on the way towards the full communion to be restored between their Churches. They can indeed, from now on, proclaim together before the world their common faith in the mystery of the Incarnation... Whatever our Christological divergences have been, we experience ourselves united today in the confession of the same faith in the Son of God who became man so that we might become children of God by his grace. We wish from now on to witness together to this faith in the One who is the Way, the Truth and the Life, proclaiming it in appropriate ways to our contemporaries, so that the world may believe in the Gospel of salvation.

In 2001, due to extreme persecution of Assyrian Christians in Iraq and Syria, the Catholic Church updated its guidelines to affirm the validity of Nestorian sacraments and allow inter-communion when necessary.

the Catholic Church recognises the Assyrian Church of the East as a true particular Church, built upon orthodox faith and apostolic succession. The Assyrian Church of the East has also preserved full Eucharistic faith in the presence of our Lord under the species of bread and wine and in the sacrificial character of the Eucharist. In the Assyrian Church of the East, though not in full communion with the Catholic Church, are thus to be found “true sacraments, and above all, by apostolic succession, the priesthood and the Eucharist” (U.R., n. 15).

In conclusion, Nestorianism may still be heresy, but the Catholic Church currently does not actively denounce believers belonging to Nestorian traditions, concentrating instead on ecumenical dialog, including the affirmation that in some case, 'Nestorian' sacraments are valid.

The Assyrian Orthodox church is only one of many churches considered to be Nestorian. This site presents information on Catholic relations with varies Eastern churches. However it requires further research to know which of these are Nestorian and which are not.