Iran has repeatedly stated that it wants to wipe Israel off the face of the map, India and Pakistan are always having flare ups over Kashmir and religion and they all kill people in so called honour killings and for blaspheming against a mythical being, so with a mentality like that they can not really be trusted to have control of nukes.
At least the USA, the UK and even Russia have the sense and responsibility and have proven they are capable of not starting a nuclear war and have only used a nuke in anger twice, and that was in order to save thousands of lives and to shorten the war.
Similarly Israel, despite being continuously attacked for decades, has shown that it can control itself and has not wiped out Gaza with a low yield nuke and keeps just retaliating with what seems to be very limited force that is much less than I would have used if I was in charge to attempt to stop the attacks once and for all.