Consider holding the ceremony off-campus at a locale suitable to a graduation for a health care practitioner. Try a local hospital or an outside venue if the weather permits. While you're out of the box, perhaps have the graduates wear clothing such as medical scrubs, lab coats or all one color.
Folklore suggests that in some early cultures, "lamplighters" were rudimentary nurses or caregivers. They would pass through towns or villages with crude illuminated wicks, torches or lamps seeking and caring for the sick. Give each graduate a simple candle or small lamp. An administrator lights the lamp of the class' top achiever, who in turn lights that of another student, who passes his to the next and so on. The cycle completes when each wick is lit. Have someone speak on the symbolism of a nurse practitioner's being a beacon of hope and help.
Pinning ceremonies may be common at nursing program graduations, but what you pin on the graduate doesn't have to be common. Consider a jewel or insignia that has special or specific meaning to the school or program conferring the certification. It can be a mascot, a popular medical symbol or the abbreviation of the actual certification in prominent school colors.
Assign each graduate the task of writing a very brief story, with a word limit, about what inspired her to become a nurse practitioner. Have someone read the story as the student crosses the stage and is pinned or capped or given a certificate. A variation could be having another student write about why his fellow graduate will be an exemplary health-care professional.