Hi there. I only have a 21 month old LO so please feel free to ignore my advice as I haven't really btdt, but when E started at nursery she was still taking a morning nap and sometimes a CN or EBT, but the room she was going into only allowed for one nap at 12.30. I worried about it to begin with but E just sort of sorted it herself and adjusted.
IIWM in your situation I'd probably keep going as I am for now as there's quite a while before January and your DS could start to move towards dropping the nap anyway before them. There's so much going on at nursery and ore-school he'll probably manage without a nap, even if he needs an earlier Bt to cope to begin with and keeps the naps on days at home for longer until he adjusts properly.
If in the meantime, you feel he's heading towards dropping the nap anyway, you can do help him to do so.