Lets be honest, anywhere on the planet the US would beat the absolute shit out of Russia if we felt like it.
They'd be a tougher fight than our recent opposition of the last 30 years or so sure.. but there isn't a single country in the world right now that could stand up to motivated US in conventional warfare. We're way too far ahead technologically if nothiong else.
We also have a Navy and Airforce that doubles the sizes of pretty much any other military on the plantet in those departments.
As long as we don't go into Russia with a mind to settle in there, and we just go in to beat ass, they will get schooled. Shit, smartest thing to do would really be just go into the Ukraine, sweep them out then leave it at that. But if we had too..
Nukes would be their equalizer, but if they felt the need to pull that card, well, that tells you everything you'd need to know about how confident they really are in a military confrontation with us.