Russian nuclear doctorine is just words on paper and doesn't mean anything. Their nuclear doctorine already allows them to nuke any NATO country at will because "any attack by a non-nuclear power (Ukraine) supported by a nuclear power (US, UK, France) would be considered a joint attack" and "any attack by one member of a military bloc would be considered an attack by the entire alliance". And even if they didn't, there's no actual opposition that could prevent changing the doctorine as they wish.