you want to end up in chicago, or you want to go to school in chicago for the next couple years? if the former, columbia and nyu are probably going to get you farther in the chicago market than even northwestern.
uchicago on the other hand would be your best bet. are you applying there? they don't take a lot of transfers, and i believe they usually go for top 10%, but the fact that you're transferring from a school in the top20 (whereas most transfers are coming from much lower ranked schools) is going to give you a lot of weight.
i think the higher ranked schools love to have transfers on record from other prestigious schools. word is around my school that you can transfer to georgetown even at a relatively low rank for transferring (i've heard as low as top 30-40%).
and as far as northwestern, i'd give it a 95% chance.