Time is money,
Iran is delaying the counterattack and the more delay we see. The less value of the revenge
If Iran truly has a Nuclear bomb, this is the perfect time to do nuclear test and shut everyone up. This way they don’t even have to attack Israel leading to a full fledged war
Detonating a nuclear device will raise the complexity level of trying to limit the present crisis manifold, and perhaps irreversibly. All sides may not want that at the moment, including Iran.