Well technically it would digitize him but not kill him because he is immortal. Also this would mean that chief has access to weapons within the Halo universe but not actually belonging to his race. Therefore, (an I'm just assuming from your reply) would it be reasonable for Deadpool to have weapons from anywhere in the marvel universe that technically aren't of human origin. Because if so then Deadpool, in my opinion, would win by an even larger margin. This is just my opinion and it's ok if you disagree