This study explores synthesizing bio-nanocomposite films using chitosan nanoparticles, elephant yam (Amorphophallus paeoniifolius) starch, and butterfly pea (Clitoria ternatea) extract as an antioxidant. The films were characterized to assess their structural, thermal, and functional properties for potential applications in sustainable packaging. Fourier Transform Infrared Spectroscopy (FTIR) revealed enhanced hydrogen bonding between anthocyanins and the matrix, indicated by increased intensity of the broadband at 3300–3400 cm⁻¹ and pronounced C=O stretching peaks at 1640–1650 cm⁻¹ with higher butterfly pea concentrations. Differential Scanning Calorimetry (DSC) showed increased glass transition temperature (Tg) with anthocyanin addition, reflecting reduced polymer chain mobility due to hydrogen bonding and π-π interactions. Minor variations in melting temperature (Tm) suggest a balance between amorphous and crystalline phases at higher anthocyanin concentrations. Functional analyses indicated that 15% anthocyanin concentration improved UV barrier properties and antioxidant activity but slightly increased water vapor permeability, while water uptake showed minimal change. These findings demonstrate that integrating butterfly pea extract enhances the performance of bio-nanocomposite films, making them promising candidates for eco-friendly packaging applications.