This study explores the development of nontoxic biocomposite films from methylcellulose (MC) and crystalline nanocellulose (CNC). First, a methylcellulose sample (Tylose MH 50) of concentration 1.5% (w/w) and crystalline nanocellulose type-1 samples of different concentrations were prepared to obtain these biocomposite films. Films were then produced by adjusting methylcellulose solution with nanocellulose solution following the casting-evaporation methodology. The molecular interactions of crystalline nanocellulose with methylcellulose were investigated using ATR Fourier Transform Infrared (FTIR) spectroscopy. FTIR analysis of films revealed a shift of absorption peak in the region of 3200-3600 cm-1 to a lower value and found an intense peak at 1031 cm-1 with the incorporation of CNC into Tylose MH 50 film. The thermal stability of these films was examined using thermogravimetric analysis (TGA), indicating the films' higher stability than MC. Mechanical properties were measured by controlled RH by dynamic mechanical analysis (DMA), showing changes in Young's modulus from the initial slope of stress-strain plots and storage modulus (E′) as the concentration of CNC increased in films. The data were obtained from bionanocomposite films, which were not even with variations in thickness as measured by a digital micrometer. The mechanical properties of bionanocomposite films showed variation due to the varying local orientation of CNCs in MC, as it contradicts work that was previously done in this area which suggests a uniform orientation of CNCs in MC biopolymer. Further research on these biocomposite films is expected to find more significant uses.