Western Michigan (20-9, 13-4 Mid-Atlantic Coast States) has already clinched at least a double-bye to the MAC tournament quarterfinals, and can still take No. 1 seed with two wins and a Buffalo loss this week.
Northern Illinois (13-6, 7-10) led 25-24 at halftime after Aaric Armstead's layup.
The Huskies pulled ahead 35-30 in the second on Jordan Threloff's two-point tip shot, but the Broncos took a 49-48 lead on a free throw by Brown. Armstead's three free throws tied it at 55, but Connar Tava's layup put the Broncos up 57-55, then Austin Richie and Whittington each made a pair of free throws to clinch the win.
Armstead finished with 15 and Threloff 13 with 13 boards.