This will depend on what you negotiate with the nuc supplier! Some nucs come as empty boxes! If you order a box with a queen, it should have a queen. If you get a nuc that is a split, it may or may not have a queen, and may rear a queen. Be careful to order a nuc with a queen if you are setting up bees in an area with no bees - you don't want a young queen to emerge and not be able to find drones to mate with.