Nurse sharks also known as vampire sharks, while having fang like front teeth and a haunting name, are actually very to themself kind of animals.
Although if it feels slightly harmed or bothered in any sort of way, it will do what it thinks it can to protect itself.
Nurse sharks usually coast the bottom of the ocean, so most reported nurse shark attacks have been of people accidently stepping or kicking on the shark, unfortunately the odds of stepping on one of these sharks are actully pretty high being that nurse sharks tend to stay within a 2 mile range of the shore.
But the actual bite itself is only slightly worse than the spinner shark which is very similar in breed and traits.