No evidence given. Recurring pro-Kremlin narrative that US and NATO nuclear policies are bringing the world closer to nuclear war. See previous cases here and here.
The current US nuclear strategy is detailed in the Nuclear Posture Review [NPR], issued by the Department of Defence in February 2018. The 2018 NPT states that “Nuclear forces, along with our conventional forces and other instruments of national power, are therefore first and foremost directed towards deterring aggression and preserving peace. Our goal is to convince adversaries they have nothing to gain and everything to lose from the use of nuclear weapons. In no way does this approach lower the nuclear threshold”.
The Review states that the US would consider the use of nuclear weapons only under “extreme circumstances” to defend the vital interests of the US, its allies and partners. It defines “extreme circumstances,” to include both nuclear attacks and “significant non-nuclear strategic attacks” against “U.S., allied or partner civilian population or infrastructure, and attacks on U.S. or allied nuclear forces, their command and control, or warning and attack assessment capabilities”
More background is available here.