I don't mean to be rude here but this just isn't wrong it's very naive.
A lot of people in this thread seem to fail to understand that the idea/concept of nuclear weapons (and the associated taboos) is completely different in the west to the rest of the world. Here in the west when most of us think of nuclear weapons we tend to think of an enormous fireball/mushroom cloud vaporising a city/island and oh-my-god the humanity, but those strategic nuclear weapons are not the only type of nuclear weapon, there are also tactical nukes. Tactical nukes are significantly smaller, I.E a nuclear tipped torpedo capable of eradicating a whole battleship/carrier with one hit, a nuclear SAM capable of downing an entire bomber formation, a nuclear tipped artillery shell capable of doing damage almost comparable to carpet bombing or even a precision missile capable of destroying a fortified bunker/building in one hit.
For us the two get lumped together and we generally think the use of any nuclear weapons is an unthinkable taboo, however in the former USSR and China (and NK) there is a much stronger mental detachment between strategic and tactical weapons. In these states using these weapons has much less stigma/taboo with military leaders and the public, and in some cases it's even seen as pragmatic (I.E if a tactical nuke is almost as good as sending bombers but you don't have the air superiority to send bombers it's a cost saver). It's worth noting that even in the west the use of tactical nukes is much less unpopular with generals/politicians than it is with the public, hell the entire reason the USA developed the MOAB thermobaric vacuum bomb was because they wanted the functional ability to drop tactical nukes the middle east without any of the political fallout (no pun intended) using actual tactical nukes would generate. Russia of course created their own more powerful version of the MOAB (Called the FOAB), which of course they couldn't afford to build in great numbers. However they can't reliably use their FOABs against Ukraine as the have to be dropped from bombers and if they could send in bombers they would be bombing and there would be no need for them to consider the extra expense of tactical nukes, however as mentioned above when bombing would see your bombers shot down then TNs become much more attractive from both a financial and effectiveness POV.
Many older posters may remember the infamous apocalyptic TV Movie "Threads" from the 80s? In that the thing that turned a tense situation into WW3 was when NATO sent B-52 bombers to hit a Soviet base in Iran and the Soviets defended the base with a nuclear tipped anti-air missile. It was and still is a very real example of how the differing western//non-western approaches to TNs can result in the west being surprised by others willingness to use them (for reference all of the USSRs cold war battle plans involved TNs, all of them).
When Xi says the use of nuclear weapons is a no go and Putin shouldn't even be saber rattling about them, and people think "ooh Russia can't afford to use them or they'll lose China's support" they're wrong, he's not referring to all nuclear weapons he's referring purely to strategic weapons he just isn't being specific because of the aforementioned difference in western/non-western mentality towards TNs (especially as he knows taking Taiwan may well require him to use TNs).
It's also important to note that this difference in mentality didn't magically move from the middle of Germany to the Russia/Ukraine border the day the USSR collapsed, if Ukraine still had tactical nukes and it had looked like all was lost in the early days of the war then there's a good chance they would have started flying towards Russian military targets. But obviously if Ukraine still had nukes they would never have been invaded in the first place, hell if they hadn't scrapped their Scuds a decade ago (at the behest of the USA who wanted to score points with Putin /Facepalm) they would have been safe (thanks Obama).