Azerbaijan could figure in an Israeli attack, but not as a base for Israeli forces that bomb Iran's nuclear facilities:
Even speaking privately, few Israeli officials will discuss the issue. Those who do are skeptical, saying overt use of Azeri bases by Israel would provoke too many hostile reactions. One political source did, however, say flying unmarked tanker aircraft out of Azerbaijan to extend the range and payloads of an Israeli bombing force might play a part in Israeli planning.
Though denying direct knowledge of current military thinking on Iran, the Israeli said one possibility might be "landing a refueling plane there, made to look like a civilian airliner, so it could later take off to rendezvous mid-air with IAF jets".
Even this seems unlikely. Azerbaijan has to live in Iran's neighborhood, after all.
At best, Israeli search and rescue helicopters and forces in civilian garb could base there, with damaged or malfunctioning aircraft from a strike package told to head north. Planes might land in Azerbaijan if they are too low on fuel or too damaged to return home or refuel in air.
Israel doesn't have many refueling aircraft, and they'd need to be in Israel to refuel the first planes to take off as they get airborne and wait for all planes to get aloft. It just doesn't make sense to me for the refueling aircraft to go to Azerbaijan. It makes even less sense to base a single disguised plane there. Why wouldn't all the planes need refueling? If Israel needs refueling in Azerbaijan on the way out, there are air fields there, right?
One thing that might be helpful is if an Israeli airborne warning and control aircraft bases out of Azerbaijan in order to track Iranian air space and orchestrate the attack. Now that would make sense.
Or Azerbaijan would be helpful as a base for Israeli drones to keep an eye on Iranian targets and for post-strike damage assessment.
I suspect this story is just to keep the Iranians guessing and their attention spread out.
And to make any Azeri non-combat related help seem reasonable after elevating the expectations of being a major component of any raid.
UPDATE: Azerbaijan says they won't help in a strike:
The Azerbaijani Foreign Ministry says no country will ever be permitted to use that country's soil for strikes against its neighbors.
This would seem to include allowing things like airborne warning and control and tanker support. But it doesn't seem like it would rule out post-strike plane recovery for damaged or low-fuel aircraft.
Would that refusal to assist in strikes rule out search and rescue assets or recon drones?
