Recently a mod came out for HOI4 that is fallout themed. It is very good and if you like Grand Strategy and Fallout this is very good. The game uses all available sources to try and depict the western seaboard, later on the midwest and east coast will be added. It starts with Wendell Peterson, So pre-Battle of Hoover Dam, and you can take any variety of nations to war. The steam page is here. Go check it out, and there is a discord if you want to suggest new stuff to the Devs.