Penternary nanocrystals have attracted attention in recent years due to their attractive properties. For this reason, Cu2NiSn(SSe)4 (CNTSSe) nanostructure, which is a novel candidate for penternary chalcogenide nanocrystals, have been synthesized by hot-injection technique. The crystallographic structure and morphology of CNTSSe nanocrystals were investigated by XRD and TEM analysis. However, the overall composition and elemental mapping images of CNTSSe nanocrystals were analyzed by energy-dispersive spectroscopy. Then, the CNTSSe nanocrystals were produced by spin coating method onto glass substrates in thin film form. The optical properties were characterized by UV–Vis–NIR spectroscopy. The XRD analysis exhibited the formation of kesterite phase with peaks corresponding to polycrystalline CNTSSe nanocrystals with tetragonal structure in (312), (112), (220) planes. The nanocrystals have consisted of extremely distributed, quasispherical particles with an average diameter of 12 ± 2 nm. Besides, the direct band gap and absorption coefficient of film were computed as 1.29 eV and over 104 cm−1.