I was able to grow some coral in my tank with my Nurse however none of it was frag. I would buy the live rock with it already on it. I have had my nurse for about 2years now shes close to 3ft. But like everyone said she does tend to knock over the smaller rock. However she never really goes after the smaller fish anymore.
I'd go for a different kind of shark. Something smaller, although my knowledge of sharks is to limited to give good advice on species. If you do get this going though, make sure to post pics and a video please.