Can I take any online pre-requisite courses for a nursing degree?

I am about to take an overnight shift at a psychiatric hospital--40 hours per week, for one year. As it turns out, I'm not going to have to deal with patients that much, as they will be asleep. And i'll have about 1 hour of paperwork to do. Then 8-9 hours of free time. I'm thinking I'll use this time to take an online course for a second degree---what are your suggestions? I've been interested in going into nursing school. Can I take any online courses that might count towards RN credits?
I'm at a professional crossroads. I'm open to any suggestions.

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