August 6 is a Wednesday, and the Fire don't play that day. Maybe you mean the September 6 game (as in your first post) of RBNY at Chi. (Of course, the Bucks playoffs would be over by then.)
If you want to make it a half-week stay, the USMNT plays the Concacaf SF Matchday 3 at Chicago on Wednesday September 10, against Trinidad & Tobago. Tickets are not yet available, according to
the USSoccer site. (The 6th is actually Matchday 2, with the USA playing at Cuba.)