(Nugget, by the way, is how I pronounced the word nougat when I was young, but nougat (NOOgar) is entirely different from nugget.)
Anyway, a nugget is something small but excellent and valuable, often to be found in a heap of dross. Nuggets used usually to be pieces of gold:
photo by James St. John
but nowadays they're generally dry bits of chicken in a fried crust:
Photo of Foster Farms Frozen Breast Nuggets by BrokenSphere
Luckily, sometimes you can come across nuggets of satisfying information, like the fact that in Australia or New Zealand something nuggety is likely to refer either to a stocky powerful human or other animal; and that Nugget is a sort of shoe polish, and that in New Zealand people sometimes nugget their shoes.
Word To Use Today: nugget. This word has only been around since the 1800s, and where it came from no one is sure, but there's a West-England dialect word nog, meaning a wooden block built into a masonry wall to provide a fixing for nails, which might have something to do with it.
Nougat comes from the Provençal nogat, from noga, nut, from the Latin nux.