Agricultural systems face growing difficulties in satisfying rising food demands due to mounting pressures from various abiotic and biotic stresses. In addition to the escalating impacts of climate change, persistent pests and diseases pose significant threats to crop yield and quality. While conventional agrochemicals provide immediate benefits, their lasting effects on human health and the environment have spurred growing interest in safer and more sustainable alternatives. Chitosan nanoparticles (CNPs), derived from natural biopolymers, have emerged as a promising nanotechnological solution due to their biodegradability, biocompatibility, and multifunctional antimicrobial properties. This chapter explores the role of CNPs in suppressing a broad spectrum of insect pests and plant pathogens. It highlights their ability to disrupt pest and pathogen development, serve as efficient carriers for the targeted delivery of bioactive compounds, and enhance plant immunity. Building on recent research and practical uses, this chapter underscores the vital role of chitosan nanoparticles in integrated pest management (IPM) strategies and their contribution to fostering more resilient and sustainable agricultural systems.