Nurses can work for themselves by starting their own side gig or business. For example, a nurse can start a blog, traveling nurse service, or doula service. When you don't work under someone else's supervision and own the business, you work for yourself.
Make sure you have the credentials to provide the service you're providing, and you can help people in your society with their healthcare needs. Not everyone goes to the doctor's office or a hospital for all their healthcare needs. If there's a void in your area, you can fill it by starting your own business.