It depends...is this a Charge Nurse of a unit? Probably not, if you're brandy new. In my nursing home the charge nurse is more like a unit manager, on the day shift. All the grunt work, paperwork, dealing with families, going to meetings, writing new orders, working with the doctor.
If that person whether it's Charge nurse or unit manger, they go home at 3:00. On the evening and night shifts, an LPN called "charge nurse" is the only nurse or the most experienced on the floor . The charge nurse in that situation would pass meds, chart, answer phones, be in charge of the CNA's deal with emergencies, send people out, etc etc etc....with an RN supervisor somewhere in the building to respond if you need them.
The second one is most likely what you're interviewing for. Best of luck, and do not take a job you don't feel ready for! Been there done that and it is not pretty!