Some better questions to ask - based on both histories of the U.S. and Soviet/Russian nuclear chains of command, and well-known rumors that Joseph Stalin was murdered by his inner circle:

1.) If Putin actually ordered the use of a nuclear weapon (in the current context in Ukraine), would his order be obeyed?

2.) If {same situation as #1}, would Putin quickly be removed from power, for being too dangerous for even his inner circle to tolerate?

3.) How confident is Putin that he knows the answers to 1.) and 2.)?