Creating a multisite would be the most efficient approach in this scenario. You could have a structure like this:
---> example.com
---> example.com/chile
---> example.com/argentina
---> example.com/mexico
The benefit of a multisite is that it’s easy to separate all your content from the beginning. And you can use a plugin like Multisite Post Duplicator to duplicate posts in between the subsites if you need them to appear in different places.