I applied in April as soon as they posted openings for the seasonal sales associates and I scheduled a phone interview a week later. The phone interview was really short, she just asked why I wanted to work at Nordstrom, an example of a time I went above and beyond to achieve a goal, and a couple other questions. I was still at school so she told me to come in on their next interviewing day and that I would be able to choose the department I wanted to work in (based on what would still be available since some previous seasonal employees would be coming back).
For the in-person interview, I was extremely nervous going into it and was expecting a pretty formal interview. However, I arrived 15 minutes early and right after I got there, a woman came to lead us over to the interview room where they had multiple interviews going on at the same time at tables spread out around the room. My interviewer was really nice and laid back, which made me feel much more comfortable. During the interview, she was summarizing my answers and writing them down but it was pretty low pressure--we even got off topic a couple of times so it eliminated most of my nerves. However, a couple of questions I wasn't expecting but as long as you come prepared with a few specific examples of times you have been successful or have reached a goal etc. you should be fine. Also, you don't have to have retail experience to answer the behavioral questions, you can use any examples from your life.
After she finished the questions she talked to me more about the job and then showed me around the department. She asked me a few questions about how familiar I was with the department (brands I could name and trends that were in style this season). Then she gave me a simple scenario where she was a customer and I had to pick out a few items I thought she would like. She asked me what I should do if the customer wanted to buy everything I picked out and I didn't really know so she told me that you want to try to build relationships so you should ask the customer how to contact them if there is a sale or event going on. Finally, she gave me her business card and I e-mailed her the next day to thank her and then she called me back that same day to say I got the job!