Frankly, in the event of nuclear war, I'd rather be in a country that doesn't have nuclear weapons than in one that does. Australia and New Zealand will probably come out of such a scenario ~fine; India and Pakistan will not, the US and Russia will not, neither China, nor France, nor the UK will either. For Nigeria (e.g.) to build nuclear weapons today would certainly give them some level of international sway (though it could also result in the destruction of their economy thanks to international sanctions), but it would also put them on the map where they had not been before.