I'm old ... so, I graduated a long time ago. But, I would consider getting her a gift that involves some pampering for herself or the establshment of a healthy lifestyle. Nursing school is stressful. So is the transition from student to professional. A gift that will help her establish habits that will help her cope with stress would "feel good" and also set her up to be successful in the future.
Some things that would help her have a "spa experience" in her home
A book of coupons for social activities/restaurants etc. and a promise to go with her to help spend them
Something that helps her establish (or rekindle) a fun hobby
People sometimes want to give gives of nursing equipment or supplies ... but I don't recommend that unless you know that her particular job will require she buy something special. I've never had an employer who didn't supply the tools I needed to do the job -- except for scrubs
. You might give her a gift certificate to buy scrubs or shoes IF (and only if) you know she will need to buy some.
Similarly, a good textbook (or gift certificate for one) related to the specialty of her job would also be good -- if you know that she will be needing one. That will depend on what job she takes.