Hybrid nano-chemical enhanced oil recovery (HNCEOR) has emerged as a promising next-generation strategy for maximizing hydrocarbon recovery from mature and technically challenging reservoirs through the integration of conventional chemical flooding and advanced nanotechnology. Despite substantial progress, existing research remains fragmented across material development, recovery mechanisms, modeling approaches, and field implementation. This review presents a systematic and integrated assessment of HNCEOR, providing a unified framework that links fundamental recovery mechanisms, chemical formulation design, nanomaterial functionality, simulation methodologies, optimization techniques, and field-scale applications. A key contribution of this review is the comparative evaluation of synergistic interactions between nanoparticles and conventional chemical agents, demonstrating how these hybrid systems enhance both microscopic displacement efficiency and macroscopic sweep performance through wettability alteration, mobility control, interfacial modification, and selective flow diversion. Analysis of the current literature indicates that nano-polymer systems are the most advanced candidates for industrial deployment, while functionalized and stimuli-responsive nanomaterials offer significant potential for future technological advancement. Furthermore, integrated modeling, simulation, and data-driven optimization approaches are identified as critical tools for accelerating formulation development and improving field-scale decision-making. Nevertheless, major challenges remain, including uncertainties in nanoparticle transport behavior, long-term injectivity performance, economic viability, and environmental impact assessment, which continue to constrain large-scale commercialization. Future progress will depend on the integration of smart nanomaterials, sustainable chemical formulations, and digital reservoir management frameworks. Overall, HNCEOR represents a transformat