<p>Chitosan (CTS), a naturally derived polysaccharide from chitin, exhibits intrinsic but relatively moderate antimicrobial activity, typically requiring high concentrations to achieve significant inhibition. To overcome this limitation, recent research has focused on Zn(II) complexation and nanoengineering approaches, which have demonstrated substantial improvements in antimicrobial efficacy. Reported minimum inhibitory concentration (MIC) values for CTS-Zn systems are frequently reduced compared to CTS, with enhanced activity observed against both Gram-positive and Gram-negative pathogens. This enhancement is attributed to synergistic mechanisms, including improved membrane permeability, sustained Zn²⁺ ion release, and increased surface area in nanostructured forms. This review presents a comparative analysis of CTS-Zn(II) complexes and CTS-based Zn nanomaterials, examining the impact of coordination modes, particle size, and surface charge on antimicrobial activity. Unlike previous descriptive reviews, this work systematically correlates physicochemical modifications with antimicrobial performance, highlighting that variations in synthesis strategies and material design influence the antimicrobial activity. Special emphasis is placed on Zn(II) complexation and nanoengineering approaches to enhance the antimicrobial efficacy of CTS.</p>