Emergence of bacteria and viruses, infection of aquaculture farms, the environmental pollution caused by toxin-rich wastewater generated have become an increasingly serious topic to solve. The wastewater mostly included heavy metals, organic dyes, and volatile compounds. They are abundant, cheap, and specific having unique functionalities such as binding sites that provide excellent mechanical and physical properties to the natural polymers, which can be utilized for the decontamination of wastewaters from heavy metals. Chitin and chitosan are the biopolymers which effectively applied from these natural polymeric materials for pollutant removal in aqueous environment. In recent time, the nanochitin and nanochitosan-based nano-hybrids are employed for effective adsorption of organic dyes and heavy metals contaminants from aqueous environment. The chapter provides extensive information on the source of nanochitin and nanochitosan along with the approaches of extraction and fabrication process. Moreover, use of nanochitin and nanochitosan for removal of heavy metals from aquatic environment is reviewed.