Battlefield nukes are fission. Those probably work fine. ICBMs typically carry fusion bombs. Those need regular maintenance - or the fission doesn't initiate fusion - but the 'trigger' is still a fission bomb, albeit smaller than the ones used on Japan — but not by much. Still bad, just not civilization ending.
For those of us living a continent away, the question becomes: are their ICBMs functional? My uneducated guess is that corruption has struck their missile force as badly as it has everything else.