I actually think it's very sensible to just talk to nursery about the practicalities of how you would like your son to be supported: there's no need to bring divisive terminologies into it.
Although I am quite glad for the heated debate in some sense, as I can see that I might have done harm if I had dived into any kind of "therapies" or types of support without better understanding the harm I might unwittingly do. So hopefully some light comes from the arguments, and not just heat. It's definitely worth reading the experiences of autistic people who went through ABA therapy as children - I found that very enlightening and helpful in supporting my own daughter, even if it was often uncomfortable.
The reality is probably all parents do some harm and somewhat screw their children up. But it's clear you are doing a lot of research and trying to avoid that. I do think reading some of the autistic voices critical of ABA therapy is an important part of our education as parents if we are thinking of going down that route. I find the Neuroclastic website good for this. E.g. there is an article there from a parent which captures materials from ABA providers (and her own views in italics so you can see which are which), and another from a BCBA explaining how she thinks she did harm, and how she thinks autism support needs to develop, which I found really interesting - but there are many more. Just being aware of what things like pairing, discrete trial training, planned ignoring, etc. are means you can avoid them if you think they do harm (which I do), while still accessing support for your child to learn new skills if you think that's necessary (which I also do).
It also helps you to be alert for things along the way. E.g. after a period using stickers as rewards (which lost its motivational power quite quickly!) we just used praise. But I've noticed my DD often doesn't really enjoy praise, and I wonder if that was because we overdid it, or praised her for things she felt uncomfortable doing? I think all the supports we gave worked best when we were supporting her to do things that she was already interested in doing - either by giving her a bit of support and encouragement if she was just lacking in confidence, breaking it down into more manageable steps if she was lacking in skills, or by taking away stressors in the environment that might have made it harder for her (e.g. noise, lots of people watching, lots of other things going on).
Everything gets easier as your kid gets older and can communicate more - whether verbally or some other way. Just by trying things and seeing what helps you can learn a lot about how your child learns, particularly if you keep your mind open to different viewpoints.