I hate to ask, but do you guys know of any good miniatures of a soldier armed with a Nock gun, or similar pepper box style rifle?
Those are cool. I have a feeling it might be something you will need to customize. I find it interesting that there are not more companies creating a version of a Nock gun.
What I found.
https://elitewargamesandmodels.com/product/british-rifles-firing-nocks-volley-gun/
Here is one for 3D printers. Upper right side gun. Not a bad version of the gun... and some other cool rifles!
https://cults3d.com/en/3d-model/game/more-28mm-fantasy-arsenal-of-muskets-percussion-flintlock-firearms-and-guns
I have not used Cults downloads. So no idea on whether a good place or not. These are listed as free, with the option to tip or become a patreon.