Nickel sulfide (NiS) thin films were deposited on the glass substrates by spray pyrolysis at 250 degrees C using an aqueous solution which contains nickel chloride hexahydrate and thiourea as precursors. X-ray diffraction analysis confirms that the hexagonal structure is being part of P6(3)/mmc space group of the deposited films with (100) preferred orientation and lattice parameters a = 3.441 angstrom and c = 5.320 angstrom. The optical properties, investigated through transmittance and reflectance measurements reveal that the direct band gap energy (Eg) is around 0.55 eV. The electrical study shows a metallic behavior of the current II-VI binary compound. This behavior regarding NiS II-VI binary sulfide was confirmed by numerical studies based on the density functional theory (DFT) were adopted. The ground state quantities, such as lattice parameter, bulk modulus and its pressure derivative as well as the elastic constants were obtained. The values are consistent with the stability of hexagonal structure. The band structure and the states densities of such material were studied. The results show that there is an agreement between experimental and simulation. (C) 2015 Elsevier B.V. All rights reserved.