Let us be a little more logical here.
Russia is playing its cardinal card in the Lesser Caucasus. If they let Azerbaijan take over Artsakh, then Armenia can directly push for a PP with NATO. Same story as with Georgia, but with extra spice as it would give the US a direct border with Iran and render the Russian SYRIAN B-route through the Caspian all but impracticable. This means a lot of shit sanwich for everybody. Iran, Turkey and Russia. Which would have a straight up open front with Georgia over YO and ABK while having a better strategic depth. If you think this is what the Russians want to deal with, then you are seriously misunderstanding the long term consequences of an Azeri Artsakh. It's a neutering of Armenia ala Serbia. Imagine the issues Serbia has regarding Kosovo, but with Armenia. The problem is that there's not enough cash in the fucking planet to apease the Armenians if they suffer an ethnic cleansing from Artsakh. This is going to lead to evacuation of Guymri, whic his the Russian trump card in keeping both Turkey and Georgia in check.
As for internal conflict, please man, please. That conflict exists already in Russia with a bunch of "formers" beating the shit out of eachother when they can.
Azeri territory, not really, FFS one of the biggest Soviet crimes of the Gorby era was the supression of Nakhchevan which was cleansed under the Soviet leadership. Similarly the Artsakh situation was poorly handled by Russia mostly because its bling apoplexia over the Chechen conflict and its spillover.
Russia is lucky Armenia has litterally nothing going for itself and that the cost of babysitting Armenia might be the biggest issue for new Western Sugar daddies, but for the US the rewards are huge. It can throat Iran, be a continuous nuisance for Russia and grow like a bad case of fungus in the region and who knows even take out Alyiev. That means a bigh puddle of shit for every one in the Caspian.
If Russia wants to turn the Caspian from a Russian lake into a shit lake, be my guest.
I don't believe that random countries get to ride out a free lunch just because they exist in a geostrategic location.
If Armenia commits to a pro-Russian political leaning from now on, ok maybe we can have some discussion, at this point they have nothing they can claim from us.
We have said that we will fulfil our treaty obligations but since NK isn't a part of Armenia, any fighting there isn't covered by the treaty.
Why do you think the Armenians haven't recognized NK as part of Armenia and called for treaty obligations or openly called for Russian peacekeepers? Because they want to have their cake and eat it too. They don't want to be beholden to Moscow and think that they can just get a free ride. Thankfully our government isn't falling for it.
I think you're heavily over-estimating what NATO can do here. First of all Turkey won't allow Armenia to ever be a member. Secondly, while they can certainly try, any crocodile tears about Russia not helping are meaningless until they formally request help.
Moscow needs to stop falling for the machinations of all these little men in little capitals.
Finally as others have said, we are certainly beefing up their security.