China, India and Pakistan, all three of them nuclear powers, have been fighting a low-level conflict over Kashmir for several decades. So far none of them has nuked the others.
Presumably, they realise the consequences of dropping a nuclear bomb in a region of the world with a couple billion people or three.
Didn't know much about this conflict, thank you for educating me. One other difference between those combatants and a theoretically nuclear armed Ukraine is that that war is more widely seem as an existential threat to an independent Ukraine. Kashmir political disagreement seems to rest on somewhat more limited territorial claims versus the desire of one party to post its military inside the other as well as to exert widespread political influence.
And no one has lost any territory to the other since they developed nuclear weapons. All conventional millitary conflicts date from before they became nuclear powers.
Presumably, they realise the consequences of dropping a nuclear bomb in a region of the world with a couple billion people or three.