Given that the NC Attorney General has come out strongly against the law and said that his office will not be defending it, NC has zero chance of winning this suit. I'm not sure whether the other two branches of government are permitted to hire outside lawyers in a case like this, but if not, the case will be automatically be decided against the Gov. and Leg. when they fail to respond to the complaint. They likely have 30 days or so to do that. (I don't know whether UNC could choose to contest it independently, as they're a state institution and it may be up to the AG to defend them, as well.)
It's also telling that the Gov. McCrory is so ignorant of legal matters that he doesn't know the difference between slander and libel. (Or that neither is applicable to a situation like this.)