Jake Paul Says He'll K.O. Nate Robinson 1st Round, McDonald's Diet Fine

Jake Paul says you can bet your mortgage on him knocking out Nate Robinson early in their celeb boxing match ... which might explain him messing with Big Macs without worry.

The YouTube star was leaving BOA in L.A. Friday night when he dished on how he thinks his undercard fight with the ex-NBA star will go in November -- spoiler alert, the dude's very confident, so much so ... he says putting your own house on the line would be worth it.

Check it out ... Jake tells us he's guaranteeing a FIRST-ROUND knockout, regardless of how much time Nate has to train. Remember, their match was originally scheduled for September, but reportedly got pushed back to the late fall ... which he seems to confirm here.

In any case, Jake's got a word of advice for people criticizing his pre-fight diet -- namely, the fact he's been spotted at McDonald's lately and getting weird stares. His suggestion ... sshhh, 'cause he says he can eat anything he wants because of how fast he'll get a K.O.

Like we said, Jake is super confident -- dare we say, cocky as hell??? Sure, that's probably accurate, 'cause he says he can basically slow walk this fight ... running ain't necessary.