My wife and I live in Connecticut. My daughter recently graduated from college and got a job in NYC. She also moved into an Apartment in NYC, however her name does not appear on the lease.
For tax purposes, is it financially advantageous for her to continue declaring herself a Connecticut resident, or should she now declare herself a NYC resident?

Well, if she does this, and NYC finds that her principle dwelling space is in NYC, then she will have to pay back taxes and penalties. NY tax law is pretty strict and they go after folks pretty regularly for this.

I would not advise her to declare Connecticut her "residence." NY will fight it and will win.

Of course people lie and cheat on their taxes all the time, and of course this would be what she would be doing. She is living and working and has a residence in NYC, so that is her home.

Agree. Pay the taxes; her income in NYC to cover them.