Is she only have accidents at naptime? In that case it would be an idea to have an earlier lunch so there is more time for the food and drink from lunch to move through her system. For sure a pullup at naptime is in order. Make sure drink is limited to more than 4-6 ounces for lunch too. Have her go potty right after lunch and then do something quiet like books or puzzles and then go potty again just before getting into bed.