<p>Nanocellulose (NC) is known for its excellent physicochemical properties. However, scalable, efficient, and cost-effective production methods remain a significant challenge. This study investigates a novel synergistic approach that combines a hydrated formic acid/choline chloride deep eutectic solvent (HDES) with a high-shear force homogenization (HSF). The dual-treatment system (HDES/HSF) achieved an impressive NC yield of 97.8 ± 0.3% within 2 h, and 86.9 ± 1.2% in just 0.5 h, significantly reducing the process time compared to conventional methods. Morphological characterization confirmed the efficacy of the treatment: TEM and FESEM images revealed uniform, rod-like nanocellulose fibrils with diameters decreasing from 36.9 ± 12.3 nm to 14.6 ± 3.7 nm, and an average aspect ratio of 11.31. X-ray diffraction (XRD) patterns indicated the retention of the Cellulose I crystal structure, as evidenced by prominent peaks at 14.8°, 16.5° and 22.6°, with a high crystallinity index of 81.01% observed after 0.5 h of treatment. FTIR spectra confirmed the preservation of the cellulose backbone, while the appearance of a new ester carbonyl peak at 1720 cm⁻¹ indicated partial esterification induced by HDES. Thermal analysis showed enhanced thermal stability of the resulting NC, with a maximum decomposition temperature (<i>Td</i>) of 335 ℃. Rheological tests revealed increased shear viscosities and improved viscoelastic behavior, underscoring the material’s potential for advanced applications. This study highlights the effectiveness of the eco-friendly HDES/HSF system as a sustainable, cost-efficient, and high-performance strategy for producing structurally intact and thermally stable NC suitable for large-scale applications.</p> Graphical Abstract <p></p>