Nick Diaz is very capable of beating GSP in a 5 round fight. In a two men enter one man leaves scenario he's as good as any fighter at 170 or maybe even 185. Nick is born to fight and has blossomed into one of the most skilled fighters on the planet. His cardio/work rate is unmatched by anyone in the sport and his chin is godly. He has a nasty bottom game (probably not good enough to sub GSP but almost anyone else at 170 for sure), mixed with a hyper aggressive and highly unorthodox striking style. He can take massive risks in fights (hence why his fights are so entertaining) due to A) being comfortable and able to finish a fight in any position and B) because of his aforementioned godly chin.
Born to scrap. If he wasn't pissed off all the time he'd lose his edge. The dude has a chip on his shoulder and thats what separates him from his competition. I know first hand that he's not a prick at all in RL and actually quite cool.
@ Nick Diaz ducking anyone - That's really grasping at straws. Jackass you should know as well as anyone that just because you turn a fight down doesn't mean you're ducking anyone. There are a number of reasons why a fighter might choose not to fight someone else (weight, money, timing, etc.)...I'm assuming you're referencing Jason Miller? How do you challenge someone and ask them to move up a weight class, lol. You're kidding yourself if you think Diaz would turn down a fight because he was scared...Straight from Diaz's Mouth:
I'd like to get paid something extra. Double, triple, something crazy for me to do something extra that would screw up my weight to fight at that weight. I'm not just doing it for free when I'd make the same money to fight at 170-pounds. It's twice as much work. I never didn't want to sign for that fight with Miller. They were talking about making me move weights. I said tell his ass to get in f*cking shape and make weight like I do. It's f*cking hard enough for me to make 170-pounds. He acts like he wouldn't be able to do it, he doesn't want to work hard like me, that's the problem. He can work his ass off and make 170-pounds or 175-pounds or somebody can pay me a f*cking couple million dollars and I'll move up to 185-pounds and fight him. Or he can quit getting f*cking slapped in public, I know somebody's got that sh*t on video tape. That motherf*cker doesn't want to fight me."