Tyrone Conley scored a career-high 28 points to lead the Wildcats (5-6). Dane DiLiegro added 20 points.
The Broncos took a 65-58 advantage into the final minute before the Wildcats rushed back to take the lead at 68-67 on a running jumper from Chandler Rhoads with 14 seconds remaining.
Cowels gave the Broncos the lead again with 5 seconds to play and sealed it with two foul shots with 1.6 seconds left. He was 6 for 6 from the free-throw line and finished with eight points.