This discussion may contain spoilers!
Okay first off remember: The Wolf Among Us is a prequel to Fables. A lot of the opinions on who Nerissa is are extremely biased and are completely ignorant to the graphic novels.
When Bigby has his moment of flashing back to the multiple discussions with Nerissa and Faith you are left with the option to chase her or stay there. This is probably the only hint towards a "Season 2" albeit a strong one, however this leaves a strong open endedness to what we are left with. If you are familiar with the graphic novels then realize there are far higher villains in the series than The Crooked Man. Keep in mind he was a villain by "mundies" standard, not philosophical. "The Adversary" is the primary antagonist in the Fables series. There is a complete list of possible options as to who Nerissa is because she isn't in a single issue of the Fables graphic novel. This leaves there to be not only the possibility of her being Faith but any entity in the Fables universe that overlooks the Fables as a higher power. Hell, even someone who just wants to put Bigby in the right direction so to speak albeit Bigby is NOT the main character in the Fables series but he is a major protagonist.
Point being, you should not be left disappointed if your assumption that Nerissa is Faith may be wrong. There's a hefty open-ended option for what happens next in the prequel Fables universe so brace yourself for what happens.