On RapBoard someone posted a thread where Nas was talking about the beef, unfortunately the site just got re-done last week so all the threads were lost, otherwise Id post up exactly what Nas was talking about, but this is what I remember from it...
Basically Nas said if 50 comes at him he'll 'end his career like he did to Jay'. Now, Nas didnt end his career, but he did put an asterisk on it. And 50 isnt that great of a battle rapper, he says some funny shit, but none of his lines hit that hard. He also said that he'll go after anyone thats gonna come at him sideways on a diss, including Em and Dre.
I hope 50 comes weak as fuck on this shit and then Nas just destroys him like he did with Ether.