Yes, you can't become a nurse practitioner without first becoming a registered nurse. However, if you are graduating from a nursing program you can typically register for graduate school but once you take the exam you need to submit your license information to the program.
You need to work about 2-3 years to get a Registered Nurse certification. One need to complete at least 2 years of associate degree in nursing. This will make him/her eligible to take the NCLEX exam which will finally certify that the person is a registered nurse.