Nass's spokesman Mike Mikalsen said Wednesday that Nass has decided to seek the seat in southeastern Wisconsin being vacated by retiring Sen. Neal Kedzie.
Kedzie announced on Tuesday that he was stepping down after more than 17 years in the Legislature.
Nass is a conservative from Whitewater who has been a frequent and outspoken critic of the University of Wisconsin. He also sponsored a bill signed into law that makes it easier for schools to keep Indian and other race-based mascots.
Mikalsen says Kedzie and Rep. Tyler August, who also lives in the Senate district, will be endorsing Nass.
The other state representative in the district, Republican Amy Loudenbeck, of Clinton, did not immediately return a message seeking comment.