Depends who is in command though doesn't it? With NATO composed of the UK, Netherlands, Denmark, W. Germany Belgium - they sure don't want to use nukes in Europe.
My understanding is the Head of Nato was always an American. Or ground forces. Something like that. In truth, I am a little fuzzy on it (fuzzy on a lot of things this morning, good night but paying for it). The reason was the US commited most of the troops and assets.
But your point of use of nukes is a very good one. Politically, it is a no-go. Militarily, it may become neccesary. My understanding of the nuke scenario is the use is Tactical, not strategic. The most common use is for interdiction of supply routes of maybe (and this is a big if) the attack on an armored thrust. The interdiction is more likely as it is a non-mobile situation whereas finding and fixing a Tank Army has got to be difficult.
I have also heard of the used of tactical nukes in everything from torps to depth charges in use against US Battle Groups, Re-supply convoys or attacking enemy subs.
The problem with all the scenarios is, once the button gets pushed, even on a limited, local basis, it is impossible to stop the growth in yield and expansion of targets. Especially with a sustained loss situation with air assets, you get fewer shots at a target as your sortie rate drops (due to losses) so going up in yield and type of weapon is almost a natural occurence, that is after the first one gets used.
But the first one is the trick. Nobody is going to raise their hands and volunteer to do it, but it's probably going to happen. For instance, West Germany is not going to sign on to firing a nuke on West German soil but they may ok the use in East Germany on a supply/command target that is critical to an armored thrust running rampant in West Germany. Same might be true if the target is in Poland or Checz.
In short, the initial use of nukes wouldn't be cut and dried (lets nuke Moscow) but something that is more grey and lower yield/targeting than launching a city killing 3 meg warhead at a major population center.
IMHO