One of the most effective methods for generating renewable energy is the efficient conversion of photons into electrical energy using environmentally sustainable materials. In recent years, the integration of chalcogenide materials, which exhibit graphene-like semiconducting properties and high charge carrier mobility, into perovskite solar cells (PSCs) has garnered significant attention for enhancing the performance, stability, and eco-friendly nature of these devices. In this study, Cu₂CoSnS₄ (CCTS) nanocrystals were synthesized and utilized as a fully inorganic hole transport layer (HTL) in inverted PSCs. Devices incorporating 6 vol% CCTS achieved a power conversion efficiency (PCE) of 10.07 %, and retained 93 % of their initial efficiency after 720 h under inert storage conditions, without encapsulation. This demonstrates a notable improvement in stability compared to conventional PEDOT: PSS-based devices. The optimized CCTS HTL provided better energy level alignment, reduced moisture ingress, and enhanced charge transport. These findings indicate that CCTS is a promising inorganic HTL candidate for efficient and stable PSCs.