Bachelor's Degree Programs. An aspiring RN can earn a bachelor's of science in nursing (BSN) in four years at a college or university. If you're already an RN, you can enroll in an RN-to-BSN program which is geared specifically for RNs who have an associate's degree or nursing diploma.This path usually takes about two to three years.egistered nurses (RNs) are required to have a minimum of an associate's degree, but bachelor's degrees in nursing (BSN) are also available and can help an RN's chances to earn better pay. Weigh your school options based on your current educational needs and timetable.