There are not many countries that are known to have had nuclear and/or chemical weapons, then voluntarily given them up.
South Africa did, in its transition from apartheid to liberal democracy. Kazakhstan had them on their territory as part of the USSR's nuclear arsenal, but did not wish to keep them when the Soviet Union broke up. The only other two nations I am aware of are Iraq and Libya. Saddam gave up Iraq's chemical weapons under pressure from the UN, whilst Colonel Gaddafi did so as part of his phased re-integration into the 'world community' in the 1990s. He also abandoned plans to develop a nuclear weapon. The events of 2003 and 2011 would seem to demonstrate that if you get rid of your chemical weapons, you are far more likely to be attacked by Western forces.
It appears as if the only thing the US, UK and France understand is force, and indeed force of the most barbaric type. Is that likely to reduce Iran's desire to develop nuclear weapons?