There hasn't been a firm consensus, certainly nothing established on screen, but there *is* a train of thought in the fandom that certain things in the JJTrek-verse were already different even
before Nero's incursion. One which EAS has explored in detail is Chekov, who (it turns out) probably can't be a 1:1 of 'our' Chekov, as the ages are straight out wrong (so, at the very least, Mommy and Daddy Chekov in the JJ-verse must have had their child several years apart from their Prime seves, albeit they still named him Pavel, but he probably isn't
actually biologically the same person in both universes, unlike some of the other characters who might still be effectively the same guy or gal as their Prime universe self despite any changes).
Maybe the Narada and the Jellyfish both managed to not only cross backwards in time, but also *sidewards* in space? Who knows, maybe due to the 'wildcard' that was the Red Matter being involved, if this isn't exactly what happened.