I know of nocino only from a few discussions (probably on the Calontir brewers list).  Both everclear and vodka are considered neutral spirits.  I believe everclear is usually made from grain while vodka a variety of fermentables from grain to potatoes. Biringuccio's Pirotechnica (1545) and many other sources include methods and equipment of producing aqua vita the medieval version of these neutral spirits.  Of course you would buy these not produce them yourself as that is not legal without a license.  Barrel aged versions like scotch, brandy and bourbon would all have different flavors and would not be want unless you found a specific medieval recipe saying specificly so.  Also be aweare that American black walnuts and English walnuts are two different things.  It would do you good to find out what species the modern version is made from.  I doubt that tradition has ever "switched" species although its possible.  If you find a period recipe for nocino please send it my way as I would be very interested.  Also check out Digby, and Hugh Plat's delights for ladies .  There might have been something in there. I don't have them available right now.

Master Gerald Goodwine