In July, Iran and the P5+1 agreed on the 15-year Joint Comprehensive Plan of Action. This plan stimulated much discussion about whether Iran would be more or less likely to develop nuclear weapons. In other words, there is a potential Predictit market.
I suggest language and rules similar to the current Predictit market for North Korea:
"Will Iran test a nuclear weapon before July, 2030?"
The Comprehensive Test Ban Treaty Organization will certify that Iran has detonated a nuclear device at any point before the end date.
Note: the current North Korea Predictit Market includes the phrase "thermonuclear device" in its rules. Since North Korea currently has fission bombs (i.e. atomic, not thermonuclear), the prediction market is actually a double bet:
*Will North Korea upgrade to h-bombs, and
*Will North Korea test an h-bomb this year.
The language I suggest for the Iran market rules avoids this wrinkle.