The effect of axial deformation on tuning the hydrogen storage of nickel functionalised (8,0) zigzag boron nitride nanotube is investigated by using density functional theory calculations. The assessment has been carried out based on the adsorption of molecular hydrogen with the binding energy lying in the desirable energy window, charge transfer, the density of states, pairwise and nonpairwise additivty, frontier orbital band gaps, isosurface plots, polarizabilities and hyperpolarizabilities, simulated Infrared (IR) and Raman (R). The numerous changes in adsorption energy of H-2 upon relaxation or compression of only (1%) strain points to the sensitivity of H-2 binding to axial deformation effects. The calculated pairwise and non-pairwise additive components show that the role of the BNNT is not restricted to support the metal. Spectral analysis additionally as polarizability and hyperpolarizability calculations characterise the relaxed structure (Z = 1.01), that H-2 adsorption energy (-0.552 eV) is within the suggested energy vary for hydrogen storage, to be energetically additional desirable than the compressed structure (Z = 0.99). The results provide some way to manage and characterise the hydrogenation process of metal functionalised BNNTs by strain loading.