You are quite mental if you think that the US would use nukes in Iran. There is a reason why no country has dared to use them in more than 50 years, despite many opportunities. It wouldn't happen with any of the sane republican presidential candidates, you can be sure it won't happen with a relative dove like Obama in charge.
Netanyahu condemns West Bank arson attack, calling it 'terror' (Haaretz)
from the article: No agreement reached in Iran nuclear talks, says UN official