No chance. A nuclear strike on Iran won't achieve anything that a large number of conventional strikes would.
I don't have a remotely decent mental model of fallout etc from modern nuclear weapons - my assumptions are they're still toxic enough to be a bloody terrible idea anywhere near someone you like.
Alliances might get reshuffled as everyone realizes they need to reassess their nuclear defense and deterrence. It would fundamentally change the nature of modern warfare, not for the better. Let us hope this never happens.
If you watch action and not social media bs, the probability is close to 0%.