Upvote:5
Nontrinitarians disagree with the mainstream Christian understanding of the Trinity summarized by the Nicean council.
That does not preclude the existance of Jesus before the first century AD.
For example, Jehovah Witnesses believe Jesus was (and is) Michael the Archangel.
And Mormons believe that God the Father exists in the form of a man and that Jesus existed in the form of a man, even before his birth (Ether 3, Book of Mormon).
This is an interesting (confusing) scripture for several reasons, for example, in reconciling it with Exodus 33:20
Thou canst not see my [God's] face: for there shall no man see me, and live.
but I don't see how Nontrinitarianism would of itself make this story more difficult to explain.
FYI, if you are looking for general interpretations, see