Michael Sanders passed for 427 yards and four touchdowns - including the 27-yarder to Ford - and then hit Madison Mangum on the two-point conversion, gaining the 37-31 lead with 6:15 left to play.
Earlier in the quarter, Ford capped a nine-play drive with a TD run from the 1-yard line as the Bengals improved to 2-4 overall and 1-2 in the Big Sky.
The North Dakota (4-2, 2-1) defense forced a punt to get the ball back with 2:23 remaining, and Ryan Bartels hit Zach Adler for a 36-yard gain to the ISU 43. The six-play drive stalled and ended with a fourth-down incompletion at the ISU 39. The Bengals took a knee twice to run out the clock.