Well she sounds a bit self centered. (should fit in well in Chicago, believe me).
Yeah she has a job offer but let me tell you. My wife in a nurse, my SIL is a nurse, my aunt is a nurse and they all work here in Chicagoland. Every year there are whole new flocks of fresh nurses (and Dr Assts) coming out of the schools around here.
There is always the chance that whatever job you take doesn't pan out to be what you expect - I hear the talking often enough. So she may come up here or drag you up here and that "can't pass it up job" may not even work out. Then you (she) winds up going here and there looking for something that feels right.
I assume you are both working now (where are you at anyway?) so what is so bad about that? Is where she's at now so bad? I assume you are younger and then there should be moving up and advancement where you currently are, am I right?
The cost of things in Chicago is ridiculous! Some of the highest taxes anywhere. Parking on the streets is ALL metered - basically EVERYWHERE, and it is $5.00 and hour payable by quarters or credit card only at little pay box machines on each block. Everything costs more, more, more. Food, gas, insurance, housing. You will think they have a big, unfair tax on EVERYTHING and then they go ahead and raise taxes and tax things never taxed before. It is all f'ed up in Chicago!!! So much cronyism, crooked deals, TRAFFIC!, TRAFFIC! & TRAFFIC! plus there is TRAFFIC! It is VERY DIFFERENT driving than probobly where you are at. People around here are idiots on cellphones and each and everyone of them is more important than anyone else.
My advice? I have lived my entire 46 years here in the SW suburbs and work and drive in the city alot. People are fleeing Chicago (and IL to a lesser extent) in record numbers.
For your own sanity, health and mental well-being.............
DO NOT COME TO CHICAGO!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
Might want to consider letting her go ahead to this great dream job she has been offered and try it for a year or so and if it looks OK to her maybe you can join. Probobly do your relationship good to put it to the strength test.