My son is also 22 months and he has been on 1 nap since he was about 16 months old. He flipped between 2 naps to 1 nap and then back to 2 naps for about 2.5 months before finally settling down on 1 nap.

What works for me most of the time (sometimes nothing works!) is to get him super tired physically in the morning, and put him to bed between 30min to 1 hour right after lunch. If I put him to bed more than an hour after lunch, then he gets overly tired and would not want to nap at all. I read somewhere that toddlers need at least a 1 hour nap each day and the nap should start no later than 1:30pm.

Good luck with the transition! It took a few weeks for my son to get used to it but now he knows the 'drill'. So even if he didn't feel like napping (e.g. he was happily playing with his cars), he knew that was the schedule and he expected to be put in bed grumpily.