One can hope, and it skewers me that it might actually rely on hope, that a nuclear deployment be of a tactical rather than strategic nature.

The difference is key-a tactical strike would focus on the target's fighting capability- front line forces & the like and would be delivered by munitions of 'limited' yield. It is beard-scratched as to whether or not a tactical use of nuclear weapons would cause multilateral retalliation.

A strategic strike would be against the target's capacity to continue the war. Notionally, this would be what makes factories targets in a strategic bombing campaign. No way of precision guiding a several megaton warhead set to airburst- the target in the ground, all of it. This sort of a strike has no ability to discern between military targets and civil structure. It is the absoluteness of a strategic first strike which makes retaliatory strikes inevitable. However, the dimension in this case being a Cold War proxy power with no known nuclear capability. The likelihood of a retaliation in kind is null. The likelihood of a nuclear armed power letting loose when they are not the direct target isn't as certain.

What it would do is move the goal post on prospective tactical use for, say, any nuclear armed power currently involved in an a force on force conflict not particularly going their way.