Described herein is a method for producing a nanocomposite material, including nanofillers dispersed in a polymeric matrix. The method comprises the steps of: a) providing a starting thermoplastic polymeric material, having a crystalline structure; b) providing one or more precursors of the nanofillers; c) bringing the starting thermoplastic polymeric material into the molten state and dispersing the precursor or precursors therein; d) subjecting the precursor or precursors to in situ thermolysis, thereby generating the nanofillers directly within the melted material; and e) causing solidification of the molten polymeric material including the nanofillers, thereby obtaining the nanocomposite material. The precursor or the precursors are selected from among carbonates and acetylacetonates and the thermoplastic polymeric material is isotactic polypropylene.