Johnson was 10 of 15 from the field. Miles Seward made four 3-pointers and scored a career-high 16 points for Northern Colorado (2-6), which snapped a five-game losing streak. Jordan Wilson added 16 points, and Jordan Davis chipped in 13 for the Bears.
Cameron Coleman scored 17 points on 7 of 13 shooting for York.
Johnson scored 16 points as the Bears jumped out to 33-10 lead midway through the first half. Spencer Mathis's shot at the buzzer stretched Northern Colorado's lead to 52-18 at halftime.
Johnson had a driving, one-handed dunk and the Bears had a 30-point lead with three minutes to play.
Northern Colorado scored a season-high 91 points, and hosts Colorado State on Sunday.