My dd dropped her morning nap on nursery days by about 13 mths. Her afternoon nap was then around 12pm. Night time sleep can also make a difference, once dd was sleeping well at night and not waking at the crack of dawn she was more comfortable having only one nap and generally less grumpy at nursery.
It can be a struggle for babies/toddlers to sleep at nursery when they start, especially if they're only in a couple of days. What are the staff doing to help your dd sleep? Eg is there a separate quiet area etc?