Once you pass the NCLEX, you're an RN for life.
You have to hold a license to use it. State licensure requires that you work a minimum number of hours per year in the field to maintain an active license. You can pay a reduced fee to hold your license as inactive, but then you can't work and have to pay to activate it again. Most states require a minimum number of continuing education hours in order to re-activate an inactive professional license.
The hardest part is ever getting hired. NO ONE comes out of school knowing how to be a good nurse. The purpose of school is to teach you how to learn how to be a nurse once you get out into the world. School teaches you the bare minimum to perform, then you go out and work and learn how to get good at being a nurse. New grad nurses don't know squat. It takes years of working in the field to develop proficiency. That's true of all disciplines. Nobody ever got better at anything by not doing it.
And so with that comes hiring. As a hiring manager, a new grad who has not worked in the field for a significant period of time is useless at best and a danger to patients at worst. They've lost a tremendous amount of knowledge and skill, and they never spent any time developing what they did learn after school. A brand new nurse out of school still has months of orientation to get through to be minimally competent on their unit. Now imagine that person hasn't used anything they learned in school for two years. No one is hiring that nurse. No one.
If you go right from school to doing something non-nursing, I wouldn't plan on getting a good nursing job. Not right away at least. Your competition will be other new grads who HAVEN'T been out of school for a couple of years. How can you compete against that for a job?
Working on my master's in nursing