Is this your first job interview?
Don't be nervous, just be yourself and be professional.
Answer the questions honestly and don't forget to also ask your questions, especially about what kind of nurse-patient ratio you will have, and what kind of support is available during your shift, ie charge nurse with or without patient assignment, PCAs, etc.
Remember that even though you need a job, they also need you, so it's ok to show some confidence in who you are and what you do.
Good luck! Let us know how it went later!