Nick Young Celebrates Independence from Iggy ... With Massive 4th Party

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.

"If you perfect then be perfect I live in a world where ppl f*** up learn from it and move on," Nick wrote.

"That's life ... hate me or love me I'm still going to love life man."