Hi Doug123,
There isn’t a way to limit commenting for the users that are able to access your Axure Share prototype, but you can instead restrict access to your prototype so that only users with AxShare accounts will be able to it. You can do that by navigating to the prototype’s workspace at share.axure.com, clicking “Configure Security”, and then enabling the “Limit URL Access” checkbox option:
This will cause users visiting your prototype’s URL to be re-directed to the AxShare login page and required to log into a valid account before being able to view your prototype in the browser. I hope this is helpful!