XIAN said:
He said that Tupac really was a fan of Nas and after he found out that Nas was friends with BIG, he went after him. Nas was very popular in NY at the time (It Was Written sold 3 million) and I think Pac felt he had to go after him.
I'm not sure if that's 100% of the reason. If you listen to The Last Interview CD, Pac talks about Nas. He said that one time at the House of Blues (not necessarily the night of the concert that was just released), they ran into each other there. Pac said he approached Nas and said everything was cool, and the drama didn't involve him. But I guess It Was Written came out shortly afterward, and Pac was mad because he took "The Message" as a dis, claiming Nas was "talking that 'fake thug' shit" and "dropping little jewels in his shit" (basically putting subliminal disses), specifically these lines:
"Fake thug, no love, you gets the slug..."
"Spun around and shot one, heard shots and dropped son
Caught a hot one..."
"I got stitched up and went through,
Left the hospital that same night..."
(And this is the line that got Pac to say on "Against All Odds":
"This little nigga named Nas think he live like me
Talkin' 'bout he left the hospital, took five like me...")
I was always under the impression that this was why Pac went after Nas, especially since that's what he said in his interview, as opposed to going after him for his connection with Biggie (which wasn't nearly as strong as Jay-Z's connection with Biggie at the time).