Look up agency nurses [0]. When they're paid hourly being begged for work (as OP mentioned), it's usually for a nurse who has specialized skills that can hop between hospitals/ER/offices. Essentially, they're contractors of the agency, and the hospital pays the agency. Can't recall if they're W2 or 1099 though

[0] https://allnurses.com/what-quot-agency-nursing-quot-t441525/