(Speculation)
I am not certain that Iran would take such a risk. They are true cowards and use others (Hamas) to do their dirty work. If they do have the capability and use it, who would be implicated? Think about it.
I was thinking about it.
The Iranians would claim that it was an Israeli weapon that went off during transport. Of course, that claim would not stand up to the slightest examination, but by then it would not matter.
The key factor would be the pro-Iranian faction of the cabal that is currently running the Biden administration. They must be in a position to get the American government to stand down after Iran uses nuclear weapons. "It's for the children".
They aren't there yet. They may never get that strong.
There is also the minor point that Iran may not yet have working nuclear weapons, in spite of the progress reports coming from their research teams.
Right now, the American government appears to be supporting Israel. That may change abruptly after the current blockade of Gaza substantially reduces the population of Gaza.
It will be very difficult for America to claim the "high moral ground" when we start to see heart-rending videos of Gazan women and children dying from starvation and thirst.
It has been over five days since the water was stopped. Those deaths are already occurring in numbers and will be increasing to catastrophic levels soon. That is the entire point of siege warfare after all. We have forgotten so much.
Somebody will get the videos out of Gaza and my guess is that American politicians will cave and allow "humanitarian aid" into Gaza. They will also demand a cease-fire to allow distribution of humanitarian aid.
Of course, all of those supplies will be taken by Hamas fighters to sustain their activities. A "cease fire" will allow Hamas to rearm and reposition their forces. That will bog down the IDF in Gaza and increase casualties.
That would be the best time for Iran to use a nuke - if they have any. If not, they can order Hezbollah to begin a full-scale attack on Israel from the north. And they can close the strait of Hormuz to commercial traffic. "It is Israel's fault for engaging in genocide of the Palestinian people", they will say.
The horrible truth is they won't be wrong about genocide. Expulsion or extermination of the Gaza Palestinians is the answer to the problem there. All other pathways have been tried and failed decisively. The "Final Solution" will scar Jewish culture for many generations to come. But there will be generations to come.
Hezbollah has access to anti-ship missiles which are capable of sinking our aircraft carriers. Our guys will need to keep well clear of them - or have "rules of engagement" that direct us to fire on any such installations as soon as they are discovered. Waiting until fired upon is a guarantee of death.
"Do unto others before they do unto you" would be a more suitable policy.