The hydrogen storage of bending deformed Ni-functionalized (8, 0) single-walled boron nitride nanotube is investigated by using the state of the art density functional theory calculations. The Ni atom prefers to bind directly above a N site BNNT-?=0,15,30 structures while for BNNT-?=45 the most stable site is BN site and can bind up to four hydrogen molecules with adsorption energies -0.478 eV for the undeformed BNNT-?=0 and -0.255,-0.328, -0.288 eV for the deformed BNNT-?=15, 30, 45 per hydrogen molecule, respectively are inside the Department of Energy domain (?0.2 to ?0.6 eV). With no metal clustering, the system gravimetric capacities are expected to be as large as 6.9 wt%. The bending deformed has affected the average adsorption energies per H2 molecule. The hydrogen storage reactions 4H2 + Ni-BNNT-? (?=0, 15, 30, 45) are characterized in terms of density of states, pairwise and non-pairwise additivity, molecular electrostatic potentials, infrared, Raman(R), electrophilicity, and statistical thermodynamics. Our calculations show that the enthalpies and free energies are inside the DOE domain for minimal and maximal temperatures and pressures. The closest reactions (with ?=0, 30) to zero free energy exhibit surface coverage values 0.999 and 0.973, respectively. Our calculations expect that complexes (with ?=0, 30) are promising hydrogen storage candidates.