Will Putin use nuclear weapons?

Around 2 weeks ago Putin made a statement about using every tool available to "protect Russia", which many, probably correctly, interpreted as nuclear blackmail. He also added that it's not a bluff.

Based on what I read and heard on various podcasts (as one gets his/her information today), I think Vladimir lied (no shit) and it is a bluff. Using nuclear weapons would be ineffective militarily and a political suicide.

First, the military aspect. Tactical nuclear bombs would be effective against a big concentrated mass of troops or equipment. The Ukrainian army is not like that. It's dispersed along hundreds of kilometers of front lines. Taking out a large amount of them would inevitably kill many Russian soldiers as well, not to mention that who knows where the wind sweeps the radioactive dust after.

According to the military types whose opinions I heard, conventional high-precision weapons are much better to achieve whatever aim Russians have in mind with nuclear strikes. 

How would the Ukrainians react to a nuclear attack on their troops? I don't see that they would back off, but rather the opposite. And that would leave Putin in an extremely humiliating position. He used the only tool that enables Russia to pose as a great power on the world stage (having proven that not only they have a wretched economy, but a pathetic military as well), and achieved nothing.

A nuclear strike would manifest as such in the political realm as well, but against the one who launched it. Russia would break an eight-decade-old taboo. Even its stooges (Orban, American right-wingers, and some other wannabe fascists and idiots) and reluctant allies (India, China) would be forced to abandon it.

Of course, because this is one man's decision, no one can be sure. Putin might not be what we call a rational actor now, and he can see things differently. But he himself drew a line. His condition to resort to extreme measures was that Russia itself be threatened. Then he promptly declared four provinces in Ukraine to be annexed by Russia, then the Ukrainians kept conquering them back, and then? And then nothing happened. In one masterstroke, the grand strategist closed his only escape route out of this war (at any point cutting the losses, declaring victory, claiming that the Nazis have been defeated, and going home) and proved that his threats are empty and he has nothing.

And what if efficacy is not the point and Putin wants to use the nukes to terrify the Ukrainians and the West into submission by destroying not a military target, but a city? If he annihilates Kyiv, killing Zhelensky and hundreds of thousands of civilians? I think that would be the end of him. Either the chain of command would deny carrying out the order, and it would be Putin this time who would fall out of a Kremlin window after a short illness, or it would be total and complete open season for him. No more restraint from NATO and no talking about off-ramps for him.