However if the Russians firmly believe that the threat of a nuclear war would stop any retaliatory action from NATO, then they have carte blanche to use chemical weapons without any consequences. Sanctions are probably almost as tight as they can be, so there is little room for adjustment. so some form of action will be needed.
Yes, Glider, rightly so. The problem we face is that the Russians don't have the same regard for NBC weapons and their impact as we do. It is within their doctrine that the use of nuclear weapons in particular can and will be used outside of the counter strike scenario - in 1993 the Russians dispensed with the no-first strike pledge the Soviet Union maintained - and the same is with chemical weapons.
They are looking for an excuse to use them already by making false claims about the US establishing factories in Ukraine - this is the Russians making bogus excuses to "justify" their actions, - the war itself is based on the premise that Nazis run Ukraine, again a bald lie designed to convince the Russian people of why they are doing what they are doing. These things are not for the rest of the world, but designed to convince the Russian people of why the government is ordering this destruction.
In the most recent link I posted, NATO Secretary Genera Jens Stoltenburg stated that NATO will supply counter-NBC equipment to Ukraine, which ominously means that NATO won't do much else beyond the intent to send peace keeping troops into the country, which the Russians have responded with a global nuclear war threat. This of course mean that NATO probably won't do anything more.
The Russians, sadly, regard human life with a much smaller value than we do.