The preparation of new nanocomposites by combining chitosan–lignin and three different nanoparticles (NPs) of ZnO, TiO₂ and Zn₂SnO₄ was the main interest of the present work. Lignin provides enhanced UV protection in commercial products at less than a 10% blend with other material. Also, chitosan is an abundant polymer that can be applied in many industries due to its biodegradability and biocompatibility properties. ZnO, TiO₂ and SnZnO nanoparticles present increased thermal stability and UV protection, antimicrobial and antioxidant properties. Therefore, in this study, biodegradable nanocomposite membranes were prepared from a combination of chitosan–lignin (at a 1/1 molar ratio) and 0.5, 1 and 1.5%wt of ZnO, TiO₂ and Zn₂SnO₄ via the sol-cast method. The successful integration of the nanoparticles into the polymer matrix was confirmed by Fourier transform infrared spectroscopy measurements. In addition, the size and the morphology of the nanoparticles and the homogeneity of the nanocomposites were investigated using a Scanning Electron Microscope. The crystallinity of the nanocomposite membranes was studied using X-Ray Diffraction. Moreover, the water sorption capacity, water content, contact angle, water and soil stability and mechanical properties of the prepared nanocomposite membranes were analyzed. In addition, and most importantly, the UV-blocking efficiency of the prepared membranes was measured using UV-vis spectroscopy. Finally, the antioxidant and antimicrobial properties of the nanocomposites loaded with the ZnO, TiO2, and Zn2SnO4 NPs were studied using assays. As a result, the nanocomposites showed promising features for the development of food packaging and UV-protective films and for the development of new and sustainable materials.