Montana (2-2) struggled to stop North Dakota State's power running, and the Bison took advantage on their first possession of the second half.
North Dakota State opened the drive with 54 yards on nine consecutive running plays before Wentz ran a play-action bootleg to find Vaadeland for a 19-10 Bison lead.
The Bison took the lead on their opening drive when Adam Keller made the first of his five field goals. Keller connected on three more first-half field goals to give North Dakota State a 12-10 lead at the break.
Jordan Canada scored Montana's only touchdown on a 3-yard run early in the second.