Purdue and Iowa are the two teams I have the most faith in from the Big Ten. If Iowa is on with their shooting they can pile up points quickly. Illinois is another that has a good mix of size and shooters who could cause problems for a lot of teams. But they are just so inconsistent it is hard to have a ton of faith in them.
Wisconsin with their draw could find their way to the Sweet 16 but have been very underwhelmed by them this season and won't be shocked to see them exit quickly.
Edit - of course having said that, my bracket is almost always decimated by the second weekend so the final 4 will probably be all teams from the Big Ten