Shouldn’t you be considered domestic if you have US nationality?
If so,
Uchicago would be a low-mid reach and Northwestern would be a high match ED or a low reach RD.
If not,
Uchicago would be a high reach and Northwestern a reach (lower reach ED).
Chance back?
http://talk.collegeconfidential.com/what-my-chances/1741178-predict-my-results-will-chance-back.html#latest