Sources close to the production tell TMZ ... Swaggy P will be 1 of 8 guest co-hosts when the new season debuts Wednesday night. The other guests include model Slick Woods; Jane Carrey, Jim's daughter; Tallulah Willis, singer Elle King and former NFL star Rashad Jennings.

TMZ broke the story ... Nev's been searching for a new co-host since Max Joseph bounced earlier this year after 7 years on the job.

That set things in motion for MTV to begin its search. Nev himself had a list in mind and really swung for the fences ... 'cause he was down to bring Cardi B on board. No dice there, but he still got some entertaining guests.

Nick's no stranger to the spotlight. He once made out with a puppet and went on a bro date with Draymond Green but also nearly blew his hand off in this crazy 4th of July video.

Swaggy P's gonna have tough competition ... he's not the only guest co-host who knows how to grab headlines. Remember, Slick recently went into labor right after walking the runway at NYFW.