I can imagine Jason trying to steal Nightwing's identity to try and steal Dick's role as "the good son" and "the favourite". But the way this happened is just... I'm supposed to believe that Jason's face could be plastered all over New York and Bruce wouldn't rush to see what's going? That there could be talk of a murderous Nightwing (and, oh, how it hurts that apparently everyone in New York knows Nightwing exists) and the hero community at large would let it go and no-one would phone Dick and ask "hey, man, what's the issue with that city?"
I'm also apparently supposed to believe that Jason would drop Gotham for New York, but you know what, I'm just going to chant "he was calling for attention, he was calling for attention" over and over.