The relative temperature stability of the phase state, electro- and magnetotransport properties of functional metallic film nanostructures of the spin-valve type Ni/Dy/Co, in the temperature range of 460–800 K, is shown. As established, the thickness of the Dy layer within $d_{\textrm{Dy}}$ = 5–30 nm at thickness of Ni and Co layers of 5 nm and 20 nm, respectively, does not significantly affect the crystal structure of the samples, the phase composition of which corresponds to f.c.c.-Ni + quasi-amorphous-Dy + h.c.p.-Co + f.c.c.-Co. The studied functional structures are characterized by the anisotropic nature of the magnetoresistance dependencies on the direction of the applied external magnetic field in relation to the direction of the current, which does not depend on the layer thickness and temperature of treatment. The maximum value of magnetoresistance is observed in the as-deposited films at $d_{\textrm{Dy}}$ = 30 nm and is 0.5% for measurement at room temperature, and after annealing up to 800 K—at $d_{\textrm{Dy}}$ = 20 nm. The value of the coercive force does not show a pronounced dependence on the thickness of the Dy layer. Annealing the samples to 800 K leads to the growth of the value of the coercive force. A sharp change of the values of magnetoresistance and coercive force at the changing of the samples orientation in an external magnetic field allows considered this film nanostructure as a functional element of electronics.