The Wildcats (4-0) emerged from the night of major college basketball as one of 29 teams still unbeaten. Creighton, Houston and Ohio State all suffered their first setback of the season.
Lyons made three of Arizona's 12 3-point shots while Solomon Hill added 17 points and both Nick Johnson and Angelo Choi had 10.
The Wildcats shot 57 percent from the floor and hit 12-of-21 from long range. Arizona outscored Northern Arizona in the second half by 20.
Dewayne Russell paced the Lumberjacks with 13 points.