High-entropy transition metal nitrides (HENs) are renowned for their thermal stability, corrosion and oxidation resistance, and exceptional mechanical properties, endowing them suitable for use as surface protection films for structural and moving components. However, mapping relationship between broadly adjustable metal components and mechanical properties of HENs is quite complex due to their diversity of HENs components. Taking (NbMoTaW)N_x thin film as the research object, this study prepared (NbMoTaW)N_x (x = 0, 0.59, 0.80, 0.95) thin films with different nitrogen contents by regulating nitrogen flow velocity during the film growth process based on the magnetron sputtering technique. Following analysis of (NbMoTaW)N_x thin films' composition, structure, morphology, and performance, the primary influence mechanism that govern their mechanical properties were explored. The findings revealed that by manipulating nitrogen vacancy, coordinated regulation over the lattice distortions of the nitrogen and metal sublattices was achieved. Due to high degree of the nitrogen and metal sublattice distortions, the (NbMoTaW)N_0.80 sample demonstrated the highest hardness and best wear resistance performance. After excluding factors such as electronic structure, residual stress, and grain size that affect mechanical properties, a direct relationship between lattice distortions and mechanical properties of HENs films was confirmed. In summary, this research has unearthed a straightforward strategy for controlling the lattice distortions, offering a novel approach to adjust and optimize the performance of nitride films, and ultimately providing a more effective solution to address the mechanical damage issues that arise in the context of complex service environments.