Juwan Morgan had 14 points and Thomas Bryant 13 for the third-seeded Hoosiers (18-16), who were in the NIT for the fifth time, first since 2005.
The teams traded big runs in the first half which ended with Georgia Tech up 34-27 as Indiana shot just 31 percent. The Hoosiers, who average 80 points and 48-percent shooting, took a 44-43 lead after Freddie McSwain Jr. made his only baskets, a tip-in followed by a dunk with 13:28 to play.
Shortly after that, Okogie had the last five points of a 7-0 spurt to make it 56-48 with 9:36 remaining. Jackson's dunk at the 6:24 mark made it a 10-point game and the Yellowjackets hit 12 of 17 shots in the last 13 minutes. Indiana went cold down the stretch, missing six straight shots.