Both an Iranian nuke over Israel OR an Israeli nuke over Iran will affect the world economy too, but that’s where the similarities end.
An Iranian nuke over Israel moves the world towards anarchy, injustice, dishonor, and murder.
I suspect that any Israeli nuke over Iran would be done in such a way, showing Iranian intentions prior to doing it, would move the world towards justice, honor and a brighter future. And, to quote Winnie, where the world will be able to “plan and build in justice, in tradition, and in freedom a house of many mansions where there will be room for all.”
I don’t think Israel would use nukes to counter Iranian nuclear threats. Bunker-buster bombs and sabotage, perhaps a land invasion, would do the trick. It’s the land invasion and getting the bunker-busters over there that give me a headache.