This investigation explores the physiological modulation in Brassica oleracea var. italica (broccoli) in response to treatments with distinct nanoparticles and biochemical elicitors, including copper oxide (CuO), zinc oxide (ZnO), silver nitrate (AgNO3), chitosan, methyl jasmonate (MeJA), and salicylic acid (SA). The study evaluated parameters indicative of plant vitality and stress adaptability, namely chlorophyll a and b concentrations, carotenoid content, relative water content (RWC), and relative stress injury (RSI). The application of chitosan elicited the highest RWC (95.38%), demonstrating its efficacy in preserving cellular hydration under stress, with SA (92.45%) and MeJA (90.53%) closely following. Notably, SA minimized RSI (28.95%), highlighting its superior capacity for mitigating cellular damage under adverse conditions. Comparable stress-ameliorative effects were observed for ZnO and chitosan treatments, suggesting their roles in fortifying membrane integrity. In the context of photosynthetic pigment accumulation, MeJA exhibited the most pronounced effect, achieving maximal chlorophyll a (7.13 mg/g fresh weight) and chlorophyll b (2.67 mg/g fresh weight) concentrations, with SA and ZnO displaying substantial supportive effects. Conversely, AgNO3 treatment was largely ineffective, manifesting the lowest recorded chlorophyll and carotenoid levels across all experimental conditions. Collectively, the findings underscore the potential of MeJA, SA, and chitosan nanoparticles as potent modulators of broccoli's physiological processes, particularly in enhancing photosynthetic efficiency, maintaining water balance, and mitigating oxidative damage under stress conditions. However, before field application, limitations such as the uncertain long-term effects of nanoparticles on plant genomic stability and soil ecosystems, the need for field validation under variable environmental stresses, and the economic feasibility for small-scale farmers must be addressed. Future research should focus on elucidating the molecular mechanisms behind nanoparticle-mediated stress tolerance, conducting eco-toxicity assessments of nanomaterials in agricultural systems, and optimizing cost-effective delivery methods.