Not just in nursing. You might make a difference in nursing. As a nurse, you will probably deal more with paperwork and administrators than you will patients.
Still, the opportunity to touch people's lives is not restricted to nursing. Whatever you do, you can make a difference. Before I was a nurse, I held a variety of jobs in a variety of settings. I remember that every day one particular elderly gentlemen used to come into the store where I was a cashier. He enjoyed seeing people and it clearly made him quite happy to be greeted by name in a familiar manner by the workers.
One day, he came to the store, quite somber. Although my line was particularly long at that time, he declined to have someone else ring him up. When it was finally his turn, he was crying. He had just come from the veterinarian's office, where he had put his aged dog to sleep. He was so grateful for my kind words and a hug.
No matter your profession, your words and actions have an effect on those you come across. You can make or break someone's day, no nursing license required. You do not need to become a nurse to make a difference. You can start right now in any setting.