In-plane resistivity measurements as a function of temperature, magnetic field, and its orientation with respect to the crystallographic ab plane were used to study the upper critical field, Hc2, of two overdoped compositions of the iron-based superconductor Ba(Fe1−xNix)2As2, x=0.054 and x=0.072. Measurements were performed using precise alignment (with accuracy less than 0.1∘) of magnetic field with respect to the Fe-As plane. The dependence of the Hc2 on angle θ between the field and the ab plane was measured in isothermal conditions in a broad temperature range. We found that the shape of Hc2(θ) clearly deviates from the Ginzburg-Landau functional form.