Nichols threw two scoring passes to Nathan Overbay in the first half and two more to Taiwan Jones in the second as the Eagles (5-3, 4-2 Big Sky) took advantage of a depleted Bobcat team.
Among the missing from Montana State (4-3, 2-2) were six starters and two top kickers, Jason Cunningham and Eric Fisher.
Still, the Bobcats went into the fourth quarter leading 24-14, but they could not hold on as Nichols and Jones connected on scoring tosses of 20 and 38 yards. Tyler Hart finished off Montana State with a 4-yard TD run with 1:49 left.
C.J. Palmer rushed for 134 yards and a touchdown and Cody Kempt threw a pair of TD passes for Montana State.