Plus, Nero is pretty much the most retarded villain ever.
Seriously.
He sees his homeworld getting destroyed and gets sent 100 years to the past.
What does he do? Destroy the homeworld of the guy who was too slow to save Romulus.
Instead of, you know, going to Romulus himself to warn them and/or give them technology that they otherwise wouldn't get for a damn century!
Which would give them a significant advantage over the other civilizations of the galaxy.