They used to have auto rate limit set by IP, in which case I would think bots like NightBot ran in a cloud enviroment with multiple sessions over a different IP for each session. Each session would probably be in 10 or so channels, in addition to rate limiting each session. Some of these bots are ran by Twitch staff which probably also had some sort of special levels set but it’s probably not something they would talk about because they don’t want to hand it out.
Now rate limits are now per account and not connection, probably since they added the the known/verified status.
The best bet is to set your local rate limiting to be within the moderator rate limit.