Deontay Wilder -- I Wanna Bang Nia Long ... On Camera!

He may be the heavyweight champion of the world, but Deontay Wilder still has goals -- telling TMZ Sports he wants to bang Nia Long ... in a sex scene for a Hollywood movie.

See, Wilder has dreams of becoming an actor in addition to the whole boxing thing ... and clearly, he likes the idea of doing some romantic work with the star of "Love Jones," "The Best Man" and "Big Momma's House."

In fact, Wilder says he's had a HUUUGE crush on Long for years ... and in the clip, makes the ultimate pitch to be her leading man in the sack.

You gotta watch the clip -- dude's HILARIOUS!