Note: Nanomachines, or "nannies" (that's the 31st-century colloquialism,) are surprisingly durable, yet oddly fragile. You can, for instance, pound on nanny-dust with a hammer all afternoon, ruining your counter-top while failing to have an appreciable effect on the tiny devices. But take a hot pizza-stone out of the oven and set it atop the dust-pile, and you'll ruin the nannies while maybe only discoloring the counter.
This is because large things, especially large things of uniform composition, are resilient to ambient temperature changes, while very small things are not. Nannies are phenomenally complex, and while they're built to be as resilient as possible, they have nowhere to dump heat when the molecules of their environment get excited. Their tiny hulls warp, and their single-molecule circuit strands and power coils quickly denature leaving them inert.
Nanomachines are extremely unlikely to survive the wash of plasma depicted above, while armored combatants have little to worry about. Things made of flesh (including recently hardened, ultra-durable flesh) fall somewhere in the middle. If you find yourself attacked by nannies, hold your breath, close your eyes, and set yourself on fire. Then stop, drop, and roll, and hope that good skin regeneration technology is available where (and when) you live.