Not something like this, but I'd just say to the staff something like "DD told me that the children at nursery all call Jane 'smelly Jane'. Obviously I've told her that it's unkind to call names like that, but I wondered whether you've noticed anything like this going on". I did approach DS's staff about a different issue but in that kind of way and they were very helpful and made sure there was a lot of appropriate discussion and positive reinforcement going on at circle time.