Adoree' Jackson's only been in the league a few minutes and he's already making predictions ... telling TMZ Sports his old QB, Sam Darnold, will definitely be the #1 pick in the 2018 NFL Draft.
Jackson was selected 18th overall by the Tennessee Titans -- and when we saw him out in Philly right after his name was called, he was praising the man leading his old squad back in L.A.
Jackson also says USC has a real shot at a national championship and Darnold could win the Heisman.
He's not the only one who feels this way -- in fact, there's a campaign among NY Jets fans to "tank" the season to get Darnold in '18.
Not the worst idea we've heard ...