Not really. The worst sort of situation for a country to be in in terms of nuclear deterrence is to have only one nuclear weapon, because even though the threat of using it has significant power it would leave them utterly defenceless if they were to ever use one. It would be a weapon they could never realistically use, because they would be unable to deter the inevitably-devastating counter-attack, and so the threat itself would become baseless.
Having two or three isn't that much better, since it still leaves them with a finite supply and no way to replace the weapons once they reach the end of their usable lives. There's also always the possibility that a foreign power would be able to divine the locations of such a small number of bombs and be able to destroy or steal them all.
With its own program, a country can avoid all of those disadvantages by producing enough weapons to distribute them and maintaining strategic ambiguity about their exact number and location while possessing the capability to renew and replace the bombs as they age.
Terrorist groups, on the other hand, would be perfectly happy with just one nuclear bomb. Unlike a state, they don't have to worry about deterrence or their ability to carry out a second strike. But that's why the US and other countries have put a lot of effort into securing Russia's nuclear stockpile and part of the reason why there continues to be huge effort to prevent nuclear proliferation.
Having two or three isn't that much better, since it still leaves them with a finite supply and no way to replace the weapons once they reach the end of their usable lives. There's also always the possibility that a foreign power would be able to divine the locations of such a small number of bombs and be able to destroy or steal them all.
With its own program, a country can avoid all of those disadvantages by producing enough weapons to distribute them and maintaining strategic ambiguity about their exact number and location while possessing the capability to renew and replace the bombs as they age.
Terrorist groups, on the other hand, would be perfectly happy with just one nuclear bomb. Unlike a state, they don't have to worry about deterrence or their ability to carry out a second strike. But that's why the US and other countries have put a lot of effort into securing Russia's nuclear stockpile and part of the reason why there continues to be huge effort to prevent nuclear proliferation.