With LaMelo Ball reportedly open to signing a shoe contract outside of the Big Baller Brand, TMZ Sports has learned Nike has a serious interest in working with the 18-year-old.

Our Nike sources tell us ... the company is actively scouting the youngest Ball brother and even has a scout in Australia monitoring him as plays pro ball overseas.

We're told Nike has not made a formal offer at this point, but the interest is real -- and we're guessing the fact Melo has been rocking Nike shoes lately is a good sign for the Swoosh.

Of course, things could get dicey with LaVar Ball who says he's deadly serious about reviving the Big Baller Brand after a disastrous first run.