Zinc is a promising bioresorbable metal, yet its applications are hindered by its insufficient mechanical properties. This study investigates the impact of incorporating nanopowders into a zinc matrix for laser-based powder bed fusion (PBF-LB) additive manufacturing. Two types of nanomaterials (magnesium oxide, aluminum oxide) with different particle sizes (∼45 nm, 20 nm) were separately added to the zinc powder, and the mixing parameters were optimized. A significant improvement in powder flowability, particularly with smaller nanoparticles, was observed, resulting in a higher packing density in the PBF-LB process. After printing, the density of the nanocomposites was found to be lower than that of pure zinc. However, despite having the lowest density, the printed composites with the smallest nanopowders demonstrated a higher range for hardness (22.76 ± 8.31–33.23 ± 8.23) compared to other composite groups (18.86 ± 5.79–28.05 ± 9.47). This suggests a promising path for enhancing zinc mechanical properties by the addition of nanopowders.