Generally, an immigration lawyer admitted in any state can represent foreign national before the USCIS. However, if you want a Chicago based lawyer, please find it through http://www.ailalawyer.com/.
Note to Attorneys: Please don't start the discussion on multi-jurisdictional and UPL.
Lawyers are not allowed to claim we are "the best," or even to say we are specialists in Illinois. However, any immigration attorney who handles family immigration cases in Chicago should be able to advise you on an I-751.
Law Office of Mary K. Neal | www.immigratechicago.com | firstname.lastname@example.org| 773-681-1335 This answer is intended as public information about a legal topic. Answers posted here do not create an attorney-client relationship. For specific legal advice, please make an appointment to speak with an attorney in private.
This post might help you in your search:
Dhenu Savla, Esq.
This answer does not create an attorney-client relationship and is not meant to be relied upon as legal advice.