>>56297015>implying Kanto and Sinnoh are the same country.The games never use the word "country" to refer to different regions. NPCs instead say vague things like "from a far away region." Even the Strange Souvenir guy says that the item is from a different region when by your logic Alola should also be a different country.
In the Pokémon world, the word region is likey the equivalent to the word country in our world.
The word nation could also have a different meaning. Personally, I believe that the "nation" refers to a coalition of regions/countries with established Pokémon Leagues.
