Well, I'm not sure if these classify as "nursing shoes" but I have a pair of Crocs, in the pearl white. I wear them 36 hours per week at work and then another 12 hours a week at clinicals and they are the single best shoes on the planet for my back, legs and every other single part of my body.
www.crocs.com is the website. It has a place to check for store locators too. I've also see a knock off brand (Air Walks) at Payless Shoe Store just recently.
Good luck finding that perfect shoe