At first, one might think that Kazakhstan could simply do what the Ukraine is doing, accept weaponry from NATO countries and weaken Russia in a war of attrition. However, lying between China and Russia makes resupply quite difficult, and as you said, they don't have Ukraine's military strength going in. The wild cards are countries like Turkey and Iran, who are in a strong "third party" position (they have ethnic/religious ties to Kazakhstan, probably don't trust Russia or NATO). Turkey may come strongly to Kazakhstan's relief, but at great risk (as Iran would likely side w Russia, setting Turks against both neighbors). More likely, Turkey would advocate for a political solution. NATO/West may simply decide that Kazakhstan is not worth defending, too far away, not much political gain for all the risk. I think sometimes about poor Armenia, land-locked and rather forced to ally with Russia for fear of Turkic/Azerbaijan invasion (their only hope of long-term autonomy might be a Baltic-like, NATO supported, almost Israel-like confederation of Georgians/Kurds/Assyrians). Its a complicated world!