Is there any way that you can become a nurse practitioner if you don't have a Bachelor of Science in Nursing?

I go to a school that doesn't have a nursing major. Currently, I am majoring in Biology and Spanish with the hopes of applying to Physician's Assistant School in the future. I haven't made up my mind yet though. I might change my mind down the road and want to be a Neonatal Nurse Practitioner, but I don't know for sure yet. Since my school doesn't have a nursing major, I might find myself in a bit of trouble with a Bachelor of Science in Biology... is there any way you can apply to a Nursing Masters Program without being a RN already?