Every nuke has a kind of fingerprint that identifies the source. If Russia gives someone a nuke and it gets used we’ll know it was a Russian nuke.
Why would anyone give a nuke to anyone? The VLS aren’t invented in the US. If the USAF think they can have them in Ukraine and Poland, Russia is free to have them on Cuba, Venezuela and Nicaragua.
After the Putin’s ultimatum rejected based on the right of East European puppets to choose alliances, I’d like to hear the arguments why the countries in Americans can’t.