Have just read your request for information with interest. I am researching my grandmother's family, the NURSE family from Weybourne, Norfolk, England. During my research I have found the names NOURSE & NURSE used by the same family. You mention that your grandfather told you that you originated from the Vikings. Some researchers of the name NURSE in England think the name NURSE is derived from the word NORSE (Viking) and Weybourne is where the name NURSE originated from. Although it is a well known fact, the Vikings landed at Weybourne & Kelling (a neighbouring village)there is no proof of either ideas. But i do like the idea of being descended from a Viking.
I am always happy to pass on or swap any information I have for the name NURSE.