Fireworks at Nick Young's house Monday night ... with the NBA star throwing a MASSIVE party at the home he shared with Iggy Azalea in what appears to be a public declaration of his independence.
It all went down at Nick's sprawling mansion in Tarzana -- a pad complete with a basketball court, pool and working security cameras (just ask Iggy).
The place was PACKED with all sorts of people -- including a bunch of smokin' hot ladies. We're told rapper K Camp also performed.
Nick doesn't seem bothered by the split at all -- in fact, he tweeted right after Iggy blasted him last week as a cheat.