In order to be a nurse, you need to have a BSN/ADN (Although I STRONGLY recommend going right for the BSN). But do you want to get another degree ontop of the BSN? Then maybe get a degree that can compliment it. So a degree in global health, biology, bioethics, pharmacology, physiology, etc would all be great choices. Psychology and sociology would all be good choices as well!!
Here's my story (I'll keep it short!): I am just about to graduate from University next month with a BA in Health Science, Bioethics, and Environmental Biology from a very good (and HARD!) school. I volunteered at a pediatric hospital for 3 years during school where I worked with nurses to help them and met with children. I also worked on several research projects while there. I also worked on 2 disease-related research projects with the government (one may be published soon). I also worked on health-related student organizations and conferences. This is all while I was working on my undergrad and I just finished my courses a month ago! Yay! But now I would like to either do a Masters of Public health OR an ACCELERATED BSN program (which could be an option for you!). I'm still torn between which to do. An accelerated program is basically 2 consequtive years of study but you get the exact same degree as a 4-year program. The only catch is you already have to have an undergraduate degree (or almost be done one). So if you want to get a degree, then get any degree that interests you and you can apply for an accelerated BSN :)
I would recommend volunteering at some hospitals. I've volunteered at 2 hospitals. One was a small community hospital where I was basically an orderly and it was SO BORING. But then I volunteered at one of the biggest hospitals in the country and I had so many roles in several units at that hospital there was never a dull moment! So I suggest volunteering.