India and Pakistan have nukes and shoot at each other and occasionally have KIAs though not technically at war, the rhetoric between the different parties does get violent.

I don't think any of these skirmishes have ever come close to an existential threat to either party. If things ever come to that, I have little doubt that nukes would be used.

Principles, treaties, and ideals tend to go out the window when parties are backed in a corner with no alternative options.

it is not in the interest of the US to normalise the use of nuclear weapons in tactical scenarios