Most people in Hoi4 that like nuclear post-apocalyptic scenarios are into OWB, mainly because it also has mutants, cool tech, and 50s aethetics. Unless someone tries to try reverse Kaiserredux about it, it most likely won't happen
I had a daydream at work about a really cool mod idea that would never work since I can't code nor design even toozers for shit.
It would basically be a 'Unified Post-Apoc/Dystopian Fiction' world.
Imagine factions from post-apocalyptic and dystopian fiction but combine them into one world where they all exist together since their original universes tend to have the habit of focusing on a singular region of the world. Like we all know how Fallout focuses on the West/East Coast of the United States, Mad Max is set in Australia, Metro is set in Russia, and so on.
Picture this:
The West Coast of the (former) United States would be from Fallout: New Vegas with the NCR, Legion, etc. while the American South would be a zombie infested shithole like from the Walking Dead (comics cuz' TV show is shit) with a few factions like the Commonwealh. Zombie swarms and nuclear wasteland would separate the two coastlines of North America. Other factions can fill in the blanks from other post-apoc or dystopian media.
Canada would be... Are there any post-apoc / dystopian media set exclusively in Canada? I guess we could move Gilead up north in Canada since the author of the Handmaiden's Tale is from Canada, technically.
Britain would be Airstrip One from 1984, a state utterly deluded into thinking they're part of a bigger superpower called Oceania. That or an expanded Wellington Wells from We Happy Few.
Russia would be the wasteland from the Metro game series, with the Moscow Metro being contested by at least a dozen factions while the Novosibirsk Metro is slowly decaying unless they can find a fix for the Green Stuff.
Europe would probably be the technologically advanced yet incompetent German Reich from Wolfenstein: TNO (the shitty sequels are not canon) up until Russia proper so we can allow space for the Metroverse to breathe. They have a Terror Billy mechanic where despite having Jewish Wakandan technology some Amerimutt keeps undermining their regime.
Australia would (obviously) be Mad Max with factions like Immortan Joe's Citadel and the Thunderdome amongst other from the films.
Got no clue for Asia, the Middle East, Africa, and Central/South America but Japan could probably be a number of different kinds of post-apocalyptic factions and dystopian states from all sorts of native media. Biggest one I can think of is the Tokyo wasteland from Fist of the North Star, similar to Mad Max but trade cars for martial arts. That or a demon infested and bombed out Japan straight out of Shin Megami Tensei IV.