I watched their game against DePaul. While DePaul is awful, bad roster, bad coaching, I would agree NIU poses a challenge.
Their PG is a very capable scorer, who put up 34 against the Blue Demons. Even if, astonishingly, DePaul kept going under on pick and roll, he's still a very good scorer who averaged 30 in Juco.
They have a very big Swiss dude, 6'11, athletic and a good paint protector. Also foul prone, but I am not sure our bigs are a big threat to put him on the bench with fouls.
They have a couple of other big capable bodies inside and outside. I guess what I am saying is that they won't look athletically mismatched against us.
They've only lost to Marquette this season. Granted, opposition was not that strong in other games and they were never in it against the Golden Eagles. But they looked capable. I'd dare guess, contenders for top 3 in the MAC.