The seller has an obligation to provide you with a correct title assuming the misspelling is not your fault. There usually is a fee involved with getting a corrected title.
I would start at the Illinois DMV and see what they say. It might not be a problem. Some license
people are pretty easy going and some like to make things as difficult as possible. I had a Washington title with my middle initial incorrect and they wanted $25 to issue a corrected title. I never bothered to change it and when I sold
the vehicle, it went unnoticed. Best of luck from someone who was born in Illinois, lived there 35 years, and grateful I don't live there anymore.