He doesn't have Carwin's power. He did KO Big Nog, but based on his last three fights, Nogueira isn't the same fighter that fought Fedor.
He definitely isn't going to out wrestle Brock, although he does have a decent amateur background.
If he's going to survive and pull off the upset, I think it might be due to Brock overlooking him or not having the proper conditioning. In terms of skill set, Brock has the edge.
MARK MY WORDS: Junior Dos Santos will be the one who knocks Brock off.