Iggy Azalea -- Nick Wants Huge Wedding ... 'Wants To Go Out with a Bang!'

The Nick Young, Iggy Azalea super wedding ain't gonna be cheap ... so says Iggy who tells TMZ Sports the reason she's postponing the event instead of her tour is because she needs to make money!!

Iggy was at LAX when we asked her how the wedding planning was going -- Iggy told us Nick wants a full fledged MEGA-BASH with all of his friends ... and dude's got a TON of friends.

Iggy just announced the wedding will be pushed wayyy back -- thanks to her upcoming tour -- saying it probably won't happen until the end of next basketball season.