Is it time to nuke Iran? No. Even if you ignore the large difference between Hiroshima-type weapons and focused, tactical nuclear weapons, the net effect of unleashing nuclear weapons against Iran would be huge and negative. If we announce we're willing to use nuclear weapons against a Muslim country -- with no direct ties to recent attacks against the United States -- then the voices calling for jihad against America will sound all the more reasonable to millions of young men who do not want to be vaporized.
Oh, and all the flap about uranium and Niger? We could've avoided all that if the administration had heeded the National Intelligence Council's report. According to the Washington Post the NIC concluded that "The Niger story was baseless and should be laid to rest."