Two-dimensional (2D) transition metal dichalcogenides (TMDs) possess distinct optical and electronic properties, making them promising candidates for optoelectronic applications. Recently, major advances in the wafer-scale growth of TMDs using the metal-organic chemical vapor deposition (MOCVD) have enabled their integration with standard electronics. However, such materials continue to suffer from defects and unwanted doping, which lower semiconductor performance, as exemplified by poor photoluminescence (PL) yield. Chemical treatment protocols have been shown to improve the PL yield in exfoliated and CVD-grown materials. Here, using PL, Raman microscopy, X-ray photoemission spectroscopy (XPS) and density functional theory (DFT) calculations, we develop chemical treatment protocols for wafer-scale MOCVD-grown monolayer MoS₂. The postgrowth treatment uses sulfide and TFSI-based ionic salts delivered via a solution process. We demonstrate a substantial PL enhancement ranging from 23 to 50 times, depending on the underlying MOCVD growth method of the MoS₂. We present design rules for tuning chemical treatment protocols, depending on the defect densities and doping levels, allowing for successful passivation and large PL enhancements across different growth conditions. Our results demonstrate the versatility of these chemical treatment protocols and their potential to improve PL in device-relevant wafer-scale MOCVD-grown monolayer TMDs.