The Chestnut-bellied Nuthatch (Sitta castanea) is a species of bird in the Sittidae family. It is found in Bangladesh, Bhutan, Cambodia, China, India, Laos, Myanmar, Nepal, Thailand, and Vietnam.

Its natural habitats are subtropical or tropical dry forests, subtropical or tropical moist lowland forests, and subtropical or tropical moist montanes.

This species has been split by Rasmussen and Anderton (2005) into:

• The Indian Nuthatch Sitta castanea (including the older prateri of the Eastern Ghats) found South of the Ganges river.

This is the only grey-backed, rufous-bellied nuthatch in the peninsula. Similar to the next but has a smaller bill and a frosty crown that is paler than the mantle. The wing and tail patterns lack contrast and has grey centres to the chestnut undertail coverts. Resident in the Terai and Gangetic plain extending into Central India, the Eastern Ghats, Sunderbans and a disjunct population in the Western Ghats. Breeds from February to July. Different in vocalization from the next.

• Chestnut-bellied Nuthatch Sitta cinnamoventris of the Himalayas.

Sitta cinnamoventris at Jayanti in Buxa Tiger Reserve in Jalpaiguri district of West Bengal, India.

Very similar to the previous but with a heavier bill, crown and mantle of the same shade. The wing and tail markings show contrasting markings; silvery-edge to primaries, blackish inner webs to tertials and tail with large white spots in the tail. White on ear coverts does not extend into chin unlike in the former. Race almorae of Nepal and NW Himalayas has paler underparts; race koelzi of the eastern Himalayas has the female darker than in other races. Resident from Murree Hills to the Uttaranchal foothills extending to the Assam Valley, Arunachal Pradesh into the Lushai Hills.