The use of tungsten disulphide inorganic nanotubes (INT-WS₂) offers the opportunity to produce novel and advanced biopolymer-based nanocomposite materials with excellent nanoparticle dispersion without the need for modifiers or surfactants via conventional melt blending. The study of the non-isothermal melt-crystallization kinetics provides a clear picture of the transformation of poly(L-lactic acid) (PLLA) molecules from the non-ordered to the ordered state. The overall crystallization rate, final crystallinity and subsequent melting behaviour of PLLA were controlled by both the incorporation of INT-WS₂ and the variation of the cooling rate. In particular, it was shown that INT-WS₂ exhibits much more prominent nucleation activity on the crystallization of PLLA than other specific nucleating agents or nano-sized fillers. These features may be advantageous for the enhancement of mechanical properties and processability of PLLA-based materials. PLLA/INT-WS₂ nanocomposites can be employed as low cost biodegradable materials for many eco-friendly and medical applications, and the exceptional crystallization behaviour observed opens new perspectives for scale-up and broader applications.