Self-reinforced poly(lactic acid) (SR-PLA) nanocomposites have been developed for the first time by using electrospun PLA fibre mats as a starting material followed by hot-compaction. During hot-compaction, the temperature was set while hot-pressing time was varied from 10 to 60 s to optimize processing conditions. The resulting transparent SR-PLA nanocomposite films were characterized using differential scanning calorimetry (DSC), scanning electron microscopy (SEM), and tensile testing. SEM observations confirmed that SR-PLA nanocomposites can be successfully prepared under the right conditions with hot-pressing time significantly affecting the composite microstructure. DSC results revealed that all SR-PLA films had considerably higher crystallinity with more stable crystallites and also a higher glass transition temperature when compared to bulk isotropic PLA film. Furthermore, a substantial improvement in both strength and ductility of these SR-PLA nanocomposites was observed in tensile testing. Of particular interest was the notable increase in toughness of the SR-PLA nanocomposite films as a result of their unique microstructure and related failure mechanisms.