You're not wrong to be concerned, just likely off on the probabilities by orders of magnitude.

1. Tactical nukes aren't a likely step for Russia if Ukraine takes back their territory - even if they go for Crimea. Russia knows that any use of nuclear weapons is crossing a line, and that the regime is done if they do so.

2. There isn't a reason for spying on these facilities if the goal is to analyze the US' ability to launch a nuclear strike. That strike would come from a submarine sitting on the ocean floor off the coast near Moscow. And there's no real countermeasures for those missiles.