The Bison (4-2, 1-2 Missouri Valley Conference) began the drive with 46 seconds left. A defensive holding penalty gave them a first down at Youngstown State's 45. Mohler, who was 11-for-14 passing for 192 yards and three touchdowns, hit Howard on the next play.
A two-point conversion try failed, leaving the Penguins (3-3, 1-2) within five points, but Kurt Hess fumbled after being sacked by Ricky Hagen.
Youngstown State erased a 28-20 fourth-quarter deficit with a 2-yard touchdown run by Adaris Bellamy, who gained 156 yards rushing. Stephen Blose added a 38-yard field goal with 51 seconds left.
North Dakota State's D.J. McNorton gained 90 yards on 17 carries and 131 yards on six catches, including a 4-yard touchdown.