Any one can start a business. No advance degrees are necessary unless
your business includes diagnosing and treating medical problems. State
nurse practice acts do no prohibit a nurse from starting up their own
business as an Independent Nurse Contractor. Independent nurse
contractor is one who contracts with a healthcare facility for nursing
services. A contractual agreement is drawn up between you and the
institution. You will be able to negotiate your compensation, hours
worked and length of time your services will be needed.
http://www.nursecontractorguide.com