In their initial form, they were fast response medibots, design based on a jumping spider.
I figured they could be part of the tale behind the germiating idea of the first person adventure featuring the Flying Castle.
I'm okay with that. But you'll need a way to rescue people from the influence of nanites. Otherwise, every scenario becomes a war of attrition.
What you want is an electronic pulse beam weapon, such as a Beeber-like device.
That immobilizes the nanites, and then a medical flush clears them out of the system.
Of course, if your soldier is killed, then that may not work. Unless you want to try to employ friendly zombies.