Tactically against enemy forces, or strategically against their capitals?
The former I could see. Obviously we'd need to find a new "World's worse kept secret" with the Israeli bomb out of the closet, but if its used tactically, Israel on the verge of conventional collapse could probably justify it's action to the world and live on.
If it was used strategically on a large scale, however, we'd have the hottest flash point of the cold war. Soviet retaliation against Tel Aviv would not be out of question, with all that entails. Alot depends on whether the Americans are willing to accept such an Israeli overreaction and the immense ensuing carnage, or whether they'll sever their ties completely with Tel Aviv over it. There's no question that world opinion will turn sharply against Israel.
Of course the timing also matters. The earlier in the Arab assault they use their weapons, the larger the PR hit. If they essentially wait until Tel Aviv is burning, blaming them becomes more difficult, and Israel is finished regardless. If they nuke everything as soon as their lines collapse, people would still be arguing today that they lost on purpose just to justify the destruction of their foes.