I don't think Nate Robinson is a punk at all.
The guy has gotten into multiple fights with teammates, including going after one of them with a broom (or a mop, or whatever it was). His own teammates call him a "jerk". Both Larry Brown and Mike D'Antoni didn't like him, and now the Knicks are more successful without him than with him. Plus, he's one of the biggest showboats in the league, despite never winning games to back it up.
Nate is the very definition of "punk", and he'd probably make the top ten list of "player least likely to buy into ubuntu". It continually shocks me that so many Celtics fans favor taking chances on talented jerks, rather than sticking with the system that won us a championship.