Russia doesn't want to rely on its nuclear weapons entirely for deterrence. As I said, they kept the threshold for nuclear use in their official doctrine high. Nuclear use is only allowable in case of a threat to the existence of the state—an existential threat to Russia. We can argue about what that might mean.
Other people argue that Russia does allow for small-scale nuclear use. They tend to draw on things that were written in the late nineties, which is the point where Russian doctrine did come to allow for small-scale nuclear use. They draw on Russia's deployment of dual-use capabilities, of systems that you can put either a nuclear or conventional weapon on, and a certain tendency on the part of the Russian government to talk that up.
I argue that the Russian government starts talking those things up only after western pundits and officials start publicly worrying about it. I would say that what the Russians are doing is identifying things that make westerners nervous and poking at them.
I think Russia is going to keep brandishing its nuclear capability because it makes the west nervous and because it reminds everybody that Russia is one of the great nuclear powers. I think they would prefer to build up their conventional capabilities. Most of the money is going to go to their conventional capabilities.