We present remarkable improvements in the structural, morphological, and optical properties of CH3NH3PbI3 perovskite by introducing SnS. To achieve this, we prepared SnS powder hydrothermally at different SnCl2:Na2S molar concentrations. Rigorous analyses, including XRD, FTIR, SEM, and EDAX, confirmed the formation of a single-phase stoichiometric SnS. Furthermore, we deposited CH3NH3PbI3:SnS nanocomposite films on m-TiO2 substrates using the slot-die method, varying the SnCl2:Na2S molar concentrations. The XRD analysis of CH3NH3PbI3:SnS nanocomposites indicated a notable enhancement in the crystallinity of CH3NH3PbI3, attributed to the incorporation of SnS in the film. In addition, optical microscopy and AFM observations revealed that the molar concentration ratio of SnCl2:Na2S significantly influenced the surface coverage of CH3NH3PbI3:SnS nanocomposites. By carefully optimizing the SnCl2:Na2S molar concentration ratio (MAPI:SR-2), we achieved a CH3NH3PbI3:SnS nanocomposite film with a minimal surface roughness of 192 nm, low Urbach energy of 169 meV, and an optimum band gap of 1.59 eV, as evidenced by UV-Visible and PL spectroscopy analyses. These exciting results demonstrate that incorporating SnS into CH3NH3PbI3 perovskite holds excellent promise as a composite material for various optoelectronic applications. The improved properties offered by this nanocomposite can pave the way for developing more efficient and stable optoelectronic devices based on perovskite technology.