Farad Cobb chipped in with 16 points to help the Mocs (6-9, 1-1).
Tied at 51 with 13:29 left to play, the Mocs went on an 18-10 run to take a 69-61 lead with 4:48 remaining.
Samford (3-12, 1-1) responded with a 9-3 run capped by Raijon Kelly's jumper that made it 72-70 with 2:22 to play.
Both teams went cold from the field over the final 2 minutes. Connor Miller, Clide Geffrard Jr. and Kelly all missed potential go-ahead shots for Samford in the final 1:45, and then Ronrico White connected on two free throws to seal the victory for Chattanooga.
The Mocs were efficient, shooting 57.8 percent (26 for 45) for the game.
Kelly led all scorers with 27 points.
Maryland point guard Melo Trimble, considered a lock to leave the program before struggling in the second half last season, has withdrawn from the NBA draft and will return for his junior season.
Louisville's Chinanu Onuaku, who recently underwent a medical procedure to correct a heart rhythm issue detected during the combine, will keep his name in the NBA draft pool.
Andrew White III will return to the Nebraska men's basketball team next season after removing his name from the NBA draft.