We show that epitaxial nickel (fcc structure, lattice constant of 0.3528nm) nanocrystals are formed inside magnesium oxide (sodium chloride structure, lattice constant of 0.4201nm) matrix, where the misfit ranges from 3.0% to 31.3% on different interfaces. By controlling the annealing conditions, we obtained two distinct epitaxial morphologies: (1) cube-on-cube with <100>Ni // <100> MgO with a misfit of about 18.0%; and (2) <112> morphology with <112> // <002> MgO (misfit 31.3%); <111> Ni // <200> MgO (misfit 3.0%); and <110> Ni // <020> MgO (misfit 17.0%). These results on epitaxial growth of nickel on MgO with misfit ranging from 3.0% to 31.3% are consistent with the domain matching epitaxy paradigm (DME), where integral multiple of lattice planes match across the film-substrate interface. The lattice planes include all the planes in a crystal structure, not just the diffraction planes involved in the X-ray, electron and neutron scattering. The residual misfit away from the integral multiples is accommodated by the principle of domain variation, where two or three sets of domains alternate with a certain frequency to minimize the misfit close to zero. The epitaxy in the DME paradigm is defined as the film having a fixed orientation which could be the same under certain conditions. From these results on Ni epitaxy, the dominant role of planes and matching of integral multiples of planes to accommodate small to large misfit are clearly established according to the DME paradigm.