Bullshit. Pakistan has nukes. India has nukes. The USSR had nukes. Russia and China have nukes. Any rhetoric about "an Iranian nuke will be used" is just that - rhetoric. No, it won't. Because Israel is far too close to Iran. If IS had a nuke, perhaps - they might be crazy enough to actually use it. Iran isn't IS.
Israel is a horrible country, with horrible foreign policy. They're surrounded by hostile nations for the simple reason that Israel is a horribly unfairly created country. Yes, I understand why it was created.No, that doesn't excuse the Western world just plain old drawing some lines on a map and saying "this land is your land". It's amongst the most ridiculous things ever done. Much like the Versailles accord almost guaranteed some form of WWII, the creation of Israel and the way it was done pretty much guaranteed the wars of the fifties and sixties, the continuing hostilities right now, and whatever comes next. If the UN security council writes a decree tomorrow giving British Columbia to Russia, and the security council signs off on it, should Canada and the Canadians just accept it and start speaking English? If Russia then starts exporting Russians, gives second class citizenship (or outright denies citizenship) to any original inhabitant, disowns anyone who doesn't speak Russian, should the Canadians just be a-ok with it? No they shouldn't.
I'm aware that pretty much nobody likes the Palestinians - Egypt and Lebanon don't exactly help them either. The whole resettlement thing is a mess of epic proportions with no good end in sight. And so on. Still doesn't mean Israel is in any way a good guy - they've pretty much managed to repeat every mistake Germany made in the '30s, and the international community, pressured by the US, has made almost the exact same mistakes in dealing with them - up to and including the horrible appeasement idea of letting them grab some land from other countries and just adding them to their own.
Between Israel and Saudi-Arabia, the US sponsors and supports the two worst and most destabilizing regimes in the region.
And frankly, a more likely end-of-world scenario is Israel using a nuke on Iran than vice versa.