I haven't been out to a sports bar to watch a game in a few years so my information is not the best. Never been to Wills. I recommend that you edit your thread title to "Game watch Sioux Falls" or something similar to get more feedback/
Shenanigans at the Empire Mall used to have a regular Hawkeye crowd however they moved to a brand new location on the SW side recently so can't say for sure but its likely a good bet.
I have also watched games at Champps in the Western Mall when there was an I-Club chapter up here and also at Rookies on S, Louise but, sadly, both of those places have closed. Champps has been replaced by the All Day Café and I have no idea what they offer for gameday.
You can always go to one of the two BWW in Sioux Falls.