Nanocellulose and chitosan-based nanomaterials are identified as key renewable resources due to their biodegradability, abundance, and derivation from sustainable sources. Nanocellulose, derived from the most common natural bio-polymer, cellulose, offers a renewable alternative to non-renewable materials. Nanocellulose holds desirable strengths and flexibility, making it suitable for diverse applications. Similarly, chitosan-based nanomaterials, derived from chitin found in the exoskeletons of marine organisms like shrimp, lobster, and crabs, offer significant environmental benefits. Chitosan promotes waste valorization by converting marine waste into valuable raw materials. It also exhibits biocompatibility, biodegradability, and antimicrobial properties. Because of these distinctive qualities, chitosan is useful in healthcare applications, where biocompatibility is necessary. Composites comprising cellulose nanofibers with chitosan-based nanomaterials offer a potent, environmentally reliable substitute for conventional petroleum-based materials. By lowering the environmental impact of traditional materials, their practical qualities and renewability enable creative solutions in the packaging, healthcare, and other sectors. This chapter covers the manufacturing processes, properties, and applications of these biopolymers, highlighting how they have the potential to transform nanotechnology and advance environmental-friendly business practices in various industries.