Polylactic acid (PLA) is a biodegradable polymer that can replace petroleum-derived polymers and is widely used in additive manufacturing (AM) through material extrusion. The reprocessing of PLA results in a decrease in its properties, so strategies are sought to counteract this effect, such as mixing with virgin material or creating nanocomposites. Thus, two sets of nanocomposites were created based respectively on virgin PLA and a blend of PLA and reprocessed PLA (rPLA) with the addition of 0, 3, and 7 wt% of titanium dioxide (TiO₂₎ nanoparticles using a twin-screw extruder system. All blends were used for material extrusion for 3D printing directly from pellets without difficulty. Scanning electron micrographs of the surfaces of the fractured samples indicate that the nanoparticles gathered in clusters in some blends, while they were well dispersed in the polymer matrix in others. The thermal stability and degree of crystallinity of each set of nanocomposites exhibit an increasing trend with the increase in nanoparticle concentration. The glass transition and melting temperatures of PLA/TiO₂ and PLA/rPLA/TiO₂ do not differ much. Tensile tests showed that although the reprocessed material implies a deterioration of mechanical properties, in specimens with 7% nano-TiO₂, this effect is counteracted, reaching values similar to those of virgin PLA.