Mike Tyson says if the UFC superstar was his next opponent in his return to the boxing ring ... he'd beat the hell out of The Notorious -- saying, "I'ma kick his ass!"
Iron Mike went on 'The Tonight Show Starring Jimmy Fallon' on Monday to promote his new huge comeback fight with RJJ ... when Jimmy decided to play a little "Who Would Win" game.
Rocky? Mike says he'd dominate. Ivan Drago? Tyson says he'd beat that ass too. Drago's too bulky and too damn slow.