The Bison got the first bucket on a post-feed and finish from Clinton Houston to give OBU the early two-point lead.
But Jamaal Crayton tied things up with a step back jumper.
The Bison ran the score up to 9-3 before Crayton hit A.J. Luckey on a cut to the basket to cut the deficit to five.
Eventually, the Chaps took the lead and never looked back, winning 74-66.