A popular "do-it-yourself" trick involves right-clicking a Facebook page, selecting and searching for the term "InitialChatFriendsList."
Instead of spending time trying to see who is viewing your profile, the safest strategy is to control what people can see when they land on your page. If you are worried about stalkers or unwanted viewers, use Facebook’s built-in privacy tools: facebook profile viewer
While these IDs are real, they do not represent people who viewed your profile. Instead, this list is generated by Facebook’s chat algorithm. It ranks the friends you message most frequently, who are currently online, or whom you have recently interacted with on your newsfeed. The Dangerous Reality of Third-Party Apps It ranks the friends you message most frequently,
Available in select regions, locking your profile restricts anyone who isn't your friend from zooming in on or downloading your profile picture, viewing your timeline, or seeing your full-sized photos. who are currently online