I bought a great Nursing book that had sample resumes and cover letters. Look for one at a Half-Price book store, you'll likely find one there.
What it suggested was to have an Educational Experience section and a Professional Experience section and a Volunteer section if you've done any volunteering - especially if medical (flu vaccinations, teaching CPR, etc). In the Educational section, have 2 sub sections for clinical information - one for your Role Transition and the other for your entire nursing clinical experience. List the names of the hospitals and then in one paragraph list all the things you did as a SN. In the Professional section, list all your retail jobs individually. Stress the managerial and customer service aspects of each job you list. Nursing has become more "customer-service" oriented in recent years.
In your Cover letter say something like....
I have recently graduated with _____ in Nursing from ____ College where I was blessed to _______ (have a role transition in XXXspecialty or experience XXXspecialty during my clinicals, etc.) I would love (or it's been a lifelong dream, etc) to work as a Nurse in XXXXX area.
Additional qualifications I can offer you are ______(something about your customer service skills, communication, computer knowledge, etc.)
The enclosed resume highlights my professional experience and credentials and I would welcome the opportunity to discuss it with you. I am available for an interview at your convenience.
I look forward to hearing from you.
Good Luck & God Bless!