In this study, the impact of nanofillers on the performance of starch/chitosan composites produced by extrusion was investigated. Blends from three different proportions of starch/chitosan were produced and, for each blend, three different filler concentrations were tested. The natural -Na+ montmorillonite (Mt) and bamboo fibers were used as fillers. The composites were obtained using a twin-screw extruder from homo and nanostructured masterbatch pellets. The films were characterized concerning surface, mechanical, barrier, and thermal properties, as well as morphology and molecular changes. The results showed that the incorporation of Mt or bamboo fibers exhibited high water vapor barrier: films produced from only starch structured with 0.5 g Mt/100 g presented water vapor transmission of (4.9 ± 1.3) g/h m2, whereas films produced from starch/chitosan blend at proportion 75/25 structured with 1.0 g Mt/100 g presented (8.9 ± 0.5) g/h m2. Therefore, these materials showed competitiveness for their application to food packaging.