Nash is a very good facilitator even for his age. he just gets overburdened when he is tasked to carry a team by scoring. Imagine him in a Laker uniform surrounded by options like Kobe on the wing, Barnes lurking on the three point line, Gasol on the elbow and Bynum on the post...he wouldnt even have to score to be effective. he will get a stat line that says 0 points, 16 assists, 1 steal.
biggest drawback for him would be on the defensive side. he wont stand a chance against burly PG's like Deron and Westbrook.
BTW...Lakers are in the hunt for the services of Nash. Maybe with the emergence of Bynum as a 20 - 10 guy their priorities shifted towards plugging in the gaping hole that they have in the back court rather than getting something redundant. I'll rather have Gasol and Bynum than getting Howard. Howard is just too easy and predictable to defend.