Looking in Reference | Twitch Developers for “list of viewers” “list viewers” “viewer names” “current chatters”, to no avail. I would like to see the list of users that count as viewers for my channel.
There is no possible way for you to see who counts as a viewer on your channel.
The chatters endpoint you mentioned is just a list of users and bots that are connected to Twitch Chat and joined your channel, and has no relation whatsoever to if they are a viewer or not.
In addition to what Dist said, please note that the mentioned Chatters Endpoint is undocumented and thus unsupported - it may change or be removed without advance notice.