So, would protecting Estonia bring us closure to Nuclear war? What would stop Russia from taking Estonia, Latvia, or even Lithuania, or is the West ready to use

So, would protecting Estonia bring us closure to Nuclear war? What would stop Russia from taking Estonia, Latvia, or even Lithuania, or is the West ready to use a Nuclear weapon in that situation? The Lithuanian capital city, Vilnius, is 20 km from the Russian border; they wouldn't even have to cross it to level the entire city. Would NATO attack Russia proper, would the West Nuke Russia to stop the destruction of Vilnius? I'm sure Lithuania would use a Nuclear weapon to protect itself. If there is one thing that this war has shown us, it is that a country's security is in its own hands and a Nuclear Weapon is the difference between being invaded and conquered (ex: North Korea and soon to be Iran).