Licensing will probably be somewhat similar to those who got cold licenses back in the 80's. If you have zero commercial experience, you'll get sent to some plant for 3-6 months to get commercial experience (this happened to a lot of the operators who were straight from the Navy). If you have commercial experience (much more likely, given that the new plants are generally associated with established nuclear companies), they'll build a simulator along with the plant, and develop and give the training as the plant is built.
Supposedly,for a lot of the front runner new plants, getting operators licensed is on the critical path. This is due to the need to have a design sufficient to build a simulator, build the simulator, have a frozen enough design to write operating procedures, train to the operating procedures, followed by the 1-2 year license cycle, and so on.
Another interesting question is if someone is licensed at one AP1000 plant, could they be authorized to operate an essentially identical AP1000 plant at a different utility?