A good answer will reiterate your qualifications, and will highlight what makes you unique.

Good answer:

"I've been a Nurse Practitioner for the past ten years - my boss has said time and time again that without me, the hospital would fall apart. I've also taken the time to educate myself on some of the latest industry issues I regularly use (but didn't really understand the ins and outs of). What's good enough for most people is never really good enough for me."