Acrylic resin is widely used in removable dental prostheses due to its biocompatibility, low cost, and ease of handling; however, it presents mechanical limitations and a high susceptibility to microbial colonization, particularly by Candida albicans. The incorporation of nanoparticles into polymethyl methacrylate (PMMA) has been investigated as a strategy to mitigate these drawbacks. This scoping review evaluated the impacts of incorporating chitosan (CTS) nanoparticles into PMMA on antimicrobial activity and mechanical properties. A comprehensive search of the PubMed, Scopus, Web of Science, and BVS databases resulted in the retrieval of 1912 records. After removing 557 duplicates and applying the eligibility criteria, 9 in vitro studies were included. Despite methodological heterogeneity, most studies reported enhanced antifungal activity against C. albicans and improvements in mechanical properties, such as microhardness and overall strength, when CTS was incorporated. Thus, CTS appears to be a promising additive for denture base resins, with the potential to reduce denture-associated infections and increase the longevity of prostheses. Nevertheless, standardized methodologies and well-designed in vivo and clinical investigations remain essential to determine optimal concentrations, incorporation techniques, and long-term clinical performance before implementation. A scoping review design was selected due to the exploratory nature of the study and the heterogeneity of available evidence, which precludes direct comparisons and quantitative synthesis.