I do not know if anything has been posted yet on this but on 10/10/14 there was an official release that ISOC snocross is making a stop at the raceway on Feb 20-21. I'm thinking I may have to check this out as it sounds pretty interesting. I have had my sled run down the asphalt there but never thought a snocross race would be held there.
http://www.isocracing.com/chicagoland-speedway-national-feb-20-21-2015/
http://www.isocracing.com/chicagoland-speedway-national-feb-20-21-2015/