Imagining a Fallout game set outside the US is difficult. The series is so deeply invested in post-War Americana aesthetics from Vault-Tec's cheery mascot to Nuka-Cola that there are almost no other countries where a Fallout game would make sense. Even the appearance of seemingly non-American characters like the Irish-accented Cait from Fallout 4 and Colin Moriarty from Fallout 3 raises questions about travel after the Great War of 2077. If Fallout: New Vegas 2 is in the works, however, it could make sense as the first Fallout game set at least partially outside of the USA.
There's a good case for Fallout: New Vegas 2 to take place in or include areas from Mexico. Here's why a Mexico-set New Vegas 2 just might work, and some of the lore it could take advantage of.
Fallout: New Vegas' Genre
Fallout is drenched in sickly-sweet '50s and early-'60s Americana, but the exact flavor ranges from game to game. Fallout: New Vegas plays on the western as much as the apocalyptic sci-fi genre. There's a reason western games like Red Dead Redemption often have significant portions of their story set in Mexico like the western movies that preceded them. The country's history is vital to an understanding of the genre. The annexation of huge parts of Mexico created the backdrop for the USA's western frontier. The entirety of New Vegas takes place in a part of the world that was under Mexican jurisdiction until 1848, and the tropes of the American western are inseparable from its relationship with its neighbor to the south.
No character better demonstrates the importance of Mexico to the original New Vegas' conception of the western genre better than Raul Tejada, a New Vegas ghoul companion who hails from Mexico City and ends up a gun-slinging vaquero. As well as Raul's personal story, there's already quite a bit of lore about Mexico in the Fallout universe.
Mexico And The NCR
The 23rd century saw the New California Republic expand its own borders into what was once the Mexican state of Baja. In Fallout: New Vegas talking to Chief Hanlon of the NCR Rangers at Camp Golf reveals a little bit about the new nation's operations to the south. Over two decades before the events of New Vegas, he explains, the NCR built a town in what was once Baja named Rattletail. Although the residents were eventually driven out by raiders, his story establishes that there are still people living in Mexico after the war, and that it's likely part of the NCR expansionist ambitions explored in President Kimball's Mojave Campaign.
Even if Obsidian doesn't want to commit to a game fully set in Mexico, there are other options. A game set in the NCR could explore parts of Southern California, including areas across what was once the US-Mexican border. Fallout: New Vegas 2 could also include a DLC set in Mexico, similar to DLCs from previous Fallout game's like Fallout 3's The Pitt which explored regions nearby the game's main setting.
Fallout's investment in its Americana aesthetic gives the series next-to-no opportunities to explore other countries, but a game set in the American South-West has the opportunity to take players outside of the former United States for the first time without breaking its brand. Whether or not another New Vegas or equivalent third-party-developed Fallout game will be released remains up in the air. However, New Vegas' uniquely western aesthetic helped distinguish it from the other first-person Fallout games, and a journey to the south could play into the western theme even more while finally giving fans a look into the lore of other countries.
Fallout: New Vegas 2 is not confirmed to be in development.