in the case of a war between the two, the NATO would have to be on the side of Turkey... http://warisacrime.org/content/turkeyisraeli-war-words
Why do you think that? It's not like NATO always sides with the who is "right" Where does NATO and Zionism get most of its power?
Well Turkey allone wouldnt have a chance against Israels big nuclear weapons arsenal. The Palmer-Uribe Report of the UN Panel of Inquiry on the Gaza Flotilla http://www.globalresearch.ca/index.php?context=va&aid=26385
From what I've read, don't believe Turkey cares much for US help any longer. One recent article about our changing relationship with Turkey. "Turks Turned Their Backs on America Before Dumping Israel" http://www.commentarymagazine.com/2011/09/04/turkey-israel-erdogan-us/
It would be very unlikely to come to that. Turkey wouldn't be daft enough to try and invade Israel and just because Israel has nukes wouldn't mean they'd have to use them.
The only way I could see is if they were being invaded and thought there was no other option. The rest of the Middle East is to close for them to escape unharmed. Whilst they have the support of the US this isn't going to happen.