Yes, there are. However, most governments with nuclear weapons (Excluding North Korea) are stable and have their nuclear weapons under tight lock and key. No random civilian is going to get his hands on a nuclear warhead.
Even NK keeps it under tight state control as well. The problem with Iran is not that it will launch nukes, but that it might pass on nuclaer technology and weapons to its various funded terrorists groups.
What a happy coincidence that I was researching on Spain a few days ago and its anti nuclear stance.
Now let's rip apart your argument Punisher.
Which is:
A) USA has lost nukes before.
B) Hence it can't be trusted.
C) Hence we can see untrusted nations can also have nukes, example Iran.
Now let me explain the example you gave. The plane carrying the bomb was refuelling in mid air and an
accident occurred. An accident caused the planes to collide and release the bombs, not a deliberate action. Furthermore the navy found 3 out of 4 bombs within 24 hours, the last was not found because the parachute blew it out to sea.
Now in Iran's case, we have stated earlier and given enough evidence to show that Iran wants to wipe out Israel and indirectly the USA. It has a
stated end and purpose for launching nukes. It does so by funding terrorists groups, and will stoop to any means to do so.
Now do you get why your two examples don't add up? Because what it proves to the USA after it lost its bomb is that it needed better safety precautions, not that it should not have nukes.