What, exactly, are formable nations in the context of the game? That’s why we put together the ultimate guide to what these nations are and how to form them! What Are Formable Nations? In fact, there are so many formable nations that it’s tough to keep track of everything. Or how a British led United Kingdom of America would handle global conflict. With the right conditions in place, you can see what would happen if the south really did rise again. With HOI4, that mostly comes via formable nations. We love diving into a game that lets us take real history into wild and unexpected directions. It’s no secret that games like Hearts of Iron IV attract history nerds.