Potential interview

I'm an RN with over a year of experience working on a progressive care unit. I have my BSN. I thought about applying to a PRN position at another hospital to help gain more experience. The position would be on their cardiac/telemetry floor, and they do take more than what my unit takes now, such as LVADs and post-CABG. They also seem to be more like a strict cardiac floor whereas my unit is cardiac but we get other issues as well.

This would be my second interview if they were to offer one to me. The interview for the job I have now was pretty basic and it included some very basic situational/behavioral questions, but none really pertaining to any nursing skills. For this interview I am expecting them to ask actual nursing-related questions...what can I expect? And what would I tell them if they ask why I am not interested in leaving my current job and getting a part-time or full-time position at this new job? I don't want to seem like I would be giving them an answer they wouldn't want to hear...my satisfaction at my current job is very high and I am interested in the PRN position to get more experience with the cardiac patient population.