The Wildcats (14-5, 9-2 Big Sky), who opened conference play 9-0 before being swept last week at Montana State and league-leading Montana, got back on the winning track by shooting 46 percent and outrebounding North Dakota 40-28.
Josh Schuler had 12 points for the Fighting Sioux (8-12, 5-6), who had won four of their past five games.
Weber State opened the second half with an 11-0 run to take a 40-26 lead. North Dakota got within 53-48 with 6:44 remaining before Berry hit a 3-pointer that sparked a game-ending 13-3 run for the Wildcats. Berry had seven points in the spurt, and Otis had four.
Weber State hit 4 of 5 3-pointers in the second half after missing all five attempts before the intermission.