From nut + up, apparently related to go nuts and do one's nut.
Meanings
(intransitive, slang) To lose one's temper, go nuts.
And what if some shit went wrong? Pimp was known to get crazy over minor shit. I didn't know if I could trust him to pull off a job like this without nutting up in the middle of the mix. 2006, Noire [pseudonym], Thug-A-Licious: An Urban Erotic Tale, New York, N.Y.: One World, Ballantine Books, →ISBN, page 103: