Don't laugh ... Ball's new high school coach tells TMZ Sports that could EASILY happen now that Melo's announced he'll play at Spire Prep Academy this season.

"In my opinion, LaMelo Ball can be the No. 1 pick in a year or two going to the Cleveland Cavaliers," Jermaine Jackson says.

"Ain't no question about it."

Jermaine would know ... dude played several years in the Association from 1999 to 2006 and has been around the game in some capacity ever since -- and he says Melo is just THAT talented.

"He's known as that all over the world" J.J. says ... "He has a talent that, some of it just can't be taught."

Of course ... getting LaMelo to that point means Jermaine will have to navigate around LaVar Ball -- who's been known to meddle in Melo's teams.

But, Jermaine tells us he's off to a great start with the Big Baller ... and says he foresees no issues with the BBB founder.

"If LaVar's meddling in our team, we'll have conversations and we'll talk. And, I'm about what's right. It's not about who's right. It's about what's right."

Jermaine says Melo arrives in Ohio to join the team Friday and could see some run in the team's game in Philadelphia on Saturday.