I'm not sure how this works for macOS.
Most probably this is how you would do it in an active chrome window -
- ⌘+Shift+M (macOS) or Ctrl+Shift+M (others)
- Select Manage People
Or launch chrome with the guest profile command line argument.
chrome --profile-directory="Guest Profile"
Then you should see a grid consisting of user accounts in your Chrome browser.
In this grid, tap the three vertical dot icon in the top right corner of the person image, and select Remove this Person.
The grid of user profiles looks something like this -