Why won't Russia or China or Pakistan or North Korea supply Iran with nukes?

Instead of Iran slogging away developing their own nukes for years, why cannot one of those ally countries just gift Iran a few nukes? To hell with non-proliferation treaties. The USA is the biggest violator of nuke regulations, stationing it's nukes in NATO countries, that is proliferation right there. Moving your nukes outside your borders is fucking proliferation.
Why won't Russia or China or Pakistan or North Korea supply Iran with nukes?
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