China has a no first nuclear use policy, and the USSR/Russia used to but dropped it down to threats to territorial integrity.
The United States has refused to adopt a no first use policy and says that it “reserves the right to use” nuclear weapons first in the case of conflict.
Both NATO and a number of its member states have repeatedly rejected calls for adopting a NFU policy, as during the lifetime of the Soviet Union a pre-emptive nuclear strike was commonly argued as a key option to afford NATO a credible nuclear deterrent, compensating for the overwhelming conventional weapon superiority enjoyed by the Soviet Army in Eurasia.