Molecular Dynamics (MD) simulations have been carried out on pure nickel (Ni) crystal with face-centered cubic (FCC) lattice upon application of uniaxial tension at nanolevel with a speed of 20 m/s. Morse potential was employed to carry out three dimensional molecular dynamics simulations. MD simulation was used to investigate the effect of volume of Ni nanowire on the nature of deformation and fracture. The engineering stress–time diagrams obtained by the MD simulations of the tensile specimens of these Ni nanowires show a rapid increase in stress up to a maximum followed by a gradual drop to zero when the specimen fails by ductile fracture. The feature of deformation energy can be divided into four regions: quasi-elastic, plastic, flow and failure. The nature of deformation, slipping, twinning and necking was studied. Stress decreased with increasing volume and the breaking position increases.