Time will tell but I think this is a pretty bad hire. Coaching in the NBA has gotten way better over the last 10 years, the days of just hiring former players to generate some PR are over. The Eastern conference has Stevens, Spoelstra, Nurse, etc and you're gonna come to the fight with Steve Nash with no experience? I'm not sure who else was in consideration but that is a ballsy move to say the least.
He was a very smart player but that's a big leap to be put into a win now, high expectations, big market situation with no coaching experience. And while the Nets have a lot of talent, their stars are as mercurial as it gets.