I work 3 days a week, so whilst potty training DS, he was also in nursery half the week - and TBH, I think it helped! - I suppose it depends on the nursery, but we found they actively encouraged the children to potty train, (because once they're trained it's easier for them I think!) and when DS saw the other children using the little toilets, he wanted to have a go too.
Nursery encouraged us to take in lots of spares, so if you're concerned they may revert to nappies, just don't send any in and stock up on lots of cheap underpants and trousers and send him in with a bag full.
At home, we also stayed in a lot for a week or so and I would sit DS on the potty to watch some TV, which helped.
I always put DS on the potty at every nappy change a couple of months before starting properly too.
And, not very helpful for you, but it's easier to start in the summer time, as they can run around outside with no pants on, so less washing!!! - DD is 18 months now and already showing signs of being ready, whereas DS was 3yo, so I'm not sure how to go about it with her, as of course, DS understood that much more that I told him, so that's why I'm following these threads, to pick stuff up myself! good luck.