Elachista nucula is a moth of the Elachistidae family that is found in Colorado and Utah. The length of the forewings is 5–5.1 millimetres (0.20–0.20 in). The ground colour of the forewings is white with a few greyish brown scales forming an indistinct spot in the middle of the wing at the fold and another at 2/3 of the wing. The hindwings are light yellowish grey and translucent. The underside of the wings is brownish grey.