The strongest historical nation a Semi-Realistic Atompunk Military could beat? (opens in new tab)

What it says on the tin\. The military in question will belong to the hypothetical \"Atomica Republic\", from this thread: semi-realistic atompunk military? The Atomica Republic will be assumed to have an equivalent population/industry to whatever country you pick\. Obviously, we are discussing historical nations with actual industrial mechanized capabilities\. The Atomicans are basically radiation-proof as their most fantastical trait\.