The Nato headstock of an H-935
Nato is a wood species commonly referred to as "Eastern Mahogany" because it's grain is very similar to Mahogany, although it bears no actual relation to Mahogany and tends to be more dense. It comes from the Mora Tree family, which is found in Southeast Asia and is used very commonly on Asian guitars by many manufacturers other than Samick. Its density makes for more stable necks than Mahogany and tighter tone with more treble on acoustics and archtops.
Opinion: Let it also be known that it is not inherently inferior to Honduran Mahogany or any other kind of wood. Just because it's a species that happens to grow on another continent does not make it any less resonant. In fact, the density of a wood has more bearing on tone than species, and even within a species there can be much variation in density. Honduran Mahogany has become revered only because it's what happened to be used on vintage Gibsons, and that kind of bandwagon mentality is why Brazilian Rosewood nearly went extinct, and now Mahogany is also facing depletion concerns. In other words, don't be a snob about wood species, no wood is inherently superior or inferior to another, just different.