<<p he was just an immortal wizard with a gem stone giving him his powers. Pretty tough still.>>
the old nova battled the sphinx on numerous occasions, and nova was only in spidey's class. sphinx was more powerful than nova, but nova held his own on numerous occasions. i don't think the sphinx argument is gonna win you any votes here.
nef has actually CAUGHT thor's hammer. the only upper limit ever discovered on his strength was that he could not break cap's shield. other than that, no limit is known. he has super speed (whizzer) and laser vision (living laser who has utterly carved up iron man) and has proven tough enough to withstand pronged damage from all the avengers + the t-bolts - simultaneously!
BB is a long way out of his league. BB's scream is akin to a nuclear bomb. the hulk is impervious enough (according to his bio) to withstand ground zero. i would surmise (based on everything i have seen of him) CN could do the same. thing is, BB would HAVE to use his scream, it would be his ONLY chance. i don't think this is much of a fight. BB unleashes his full power, maybe he has a tiny chance. anything else BUT that full power, CN crushes him. quickly.