N. humayuni is found in the Indian state of Maharashtra, in the Western Ghats, and in Goa and Karnataka states at elevations of above sea level. Part of its range is in the Bhimashankar Wildlife Sanctuary and the Koyna Wildlife Sanctuary. It lives in or near fast-flowing, rocky, mountain streams where it hides under rocks and in crevices. It favours forested areas with dense vegetation hanging over the water, and is sometimes found at forest edges away from streams. It has been found in a large cave near Mahabaleshwar, occupying a cave ecosystem alongside Beddome's leaping frog (Indirana beddomii). The cave has a stream flowing through it, and the numerous fulvous fruit bats (Rousettus leschenaulti) that roost there have created a deep bed of bat droppings, which is inhabited by many invertebrates on which the frogs feed.