The back may be light russet and the underparts near cream buff, but much color variation exists. Both sexes have a small white patch of hair at the base of the ears.
Adult males have shoulder pouches with epauletlike hair tufts.
Cranial and dental features distinguish this genus from related genera. The head of Nanonycteris is said to have a calflike appearance. In Ghana it was observed feeding on the nectar of the flowers of Parkia clappertoniana. Nanonycteris arrived at the Parkia trees at dusk, usually just before the departure of Epomophorus gambianus, which also was feeding on the flowers. Whereas Epomophorus tended to feed only in the upper parts of the trees, Nanonycteris tended to feed on flowers all over the tree and continued to feed in the trees in varying numbers throughout most of the night.