Nick Young doesn't give one single "f**k" who wins the game ... telling TMZ Sports he doesn't care for NCAA basketball.

Swaggy P hit Nightingale nightclub in West Hollywood after his Golden State Warriors beat up on the Phoenix Suns earlier in the day ... so, we tried talking to him about March Madness.

But, Young told us straight-up, "You know, I don't give a f**k about the NCAA."

He didn't explain why ... but maybe it's because his USC Trojans didn't get an invite to the tourney this year.

Interesting note ... Swaggy's not the only one who's turning the channel -- ratings are reportedly down 3% from last year.

For those who DO care ... Villanova takes on Michigan in the NCAA Championship Monday night.