Nanocomposites (NCs) of poly(vinyl alcohol) (PVA) with chiral-modified magnesium–aluminum-layered double hydroxides (LDHs) were prepared by solution intercalation method. A novel chiral organomodified LDH was synthesized from the coprecipitation reaction of the aluminum (III) nitrate nonahydrate, magnesium (II) nitrate hexahydrate, and bioactive N-trimellitylimido-l-isoleucine amino acid in aqueous solution via simple, fast, and green method under ultrasound irradiation for the first time. The morphology and structure of the obtained material are examined by X-ray diffraction (XRD), Fourier transform infrared spectroscopy, transmission electron microscopy (TEM), and field-emission SEM techniques. The TEM and XRD structure study revealed a coexistence of exfoliated and intercalated modified LDH in PVA matrix. The effects of modified LDH contents on the thermal property of PVA films were investigated by thermogravimetric analysis method, and the results show that by the addition of the modified LDH into the PVA causes an increase in the thermal decomposition temperatures of the novel NC materials.