There are a ton of high-quality BJJ gyms in Chicago, and probably more in the surrounding areas. Just google "Chicago BJJ" and you'll find a bunch of results.
Unfortunately, I don't know which gyms in the area spend a significant amount of time on the full old-school curriculum (starting standing, dealing with punches, getting the clinch, executing the takedown, and finishing on the ground) as opposed to just focusing on the ground grappling aspect. I checked some websites and couldn't find any that specified one way or another. So you'll need to start with google, find a list of gyms that are within a convenient commute for you, then call and ask about their curriculum. Once you find some likely candidates, visit the schools, and check out the classes for yourself to see if they fit your criteria.