Paul's boxing wins came against MMA fighters. Now, he's going to box a boxer, and I expect that boxer will obliterate him.
This assumes that Tyson is actually trying to win the fight and/or obliterate his opponent. The way Tyson is talking about this fight is different than I've ever seem him talk about a real opponent. So, I think there is a good chance that Tyson isn't taking it seriously.
Also, Tyson is a very smart marketer. He knows that people want to see a match that lasts more than a round or two. So, he may not attempt to knock Paul out immediately. That would mean he isn't fighting in his traditional way (going for the early KO), which would then make the whole match illegitimate.
Anyway, who knows? If Tyson KO's him in the first 3 rounds, people will think it was a legit match. Any other outcome will call the whole thing into question (and reasonably so, IMO).