If it is nuclear warfare that Iran wants, sure Israel will suffer, but Iran will also find that the Jews have arranged for them to meet Allah.
Remember the Iran bombs are fission bombs. Think Nagasaki or Hiroshima. The next generation is fusion or H-bombs and that is what Israel has. Far larger blast.
Still enough to level a city if the yield is in kilotons. 500 kilotons from a Russian MIRV warhead would level NYC pretty thoroughly. Nagasaki and Hiroshima were only in the range of 15-20kilotons.