After a week of him taking himself to the toilet at nursery we decided to try him in big boy pants. Most of his pants have a character on the front so I explain we've got to try to keep them dry which he seems to understand and he will tell me at bedtime or toilet visits that Buzz or Spider-Man is still dry.
At nursery he's having the odd accident where he hasn't got himself to the toilet in time or has missed the toilet (he was sitting) and hit his clothes instead. We've had one accident overnight since he's asked to not wear a nappy over night. For four weeks in, we're very happy especially as it has been done to Nate's schedule.