Armillaria nabsnona is a species of fungus in the family Physalacriaceae. The species is found in the west coast of North America, Hawaii, and Japan, where it grows on decaying hardwoods, particularly species of alder. Its fruit bodies have convex to flattened orange-brown caps up to 7 cm (2.8 inches) in diameter, brown stipes, and whitish to pinkish-tan gills.