Evans' 3-pointer with 5:16 left gave Fort Wayne (11-11, 4-5 Summit) the lead for good at 59-56 and Forbes extended it to 66-60, capping an 18-6 run with 3:01 left.
Omaha (8-13, 2-7) pulled within three with 3:25 left but had two turnovers in the final 1:31 while Fort Wayne made 7 of 8 free throws.
UNO led 29-27 at halftime and 54-48 with 9:24 left. The Mastodons took their first lead of the second half briefly at 56-54. Rostampour tied it back up but the Mavericks would get no closer.
Joe Edwards added 16 points and five steals for the Mastodons, who won their third straight.
Mike Rostampour and CJ Carter scored 16 apiece to lead the Mavericks. Marcus Tyus added 12 points and Devin Patterson 10.