With the development of nuclear industry, the requirements for materials capable of operating under the conditions of ionizing radiation have increased. Such materials are nitride coatings based on titanium and chromium. In the work, using X-ray diffraction, X-ray microanalysis, nanoindentation method of Oliver and Farr, scratch testing, the structural phase state and the mechanical properties of nanostructured Cr–N and Ti–Cr–N coatings formed by vacuum-arc deposition from filtered plasma on substrates of steel 12X18H10T and alloy Zr2.5%Nb are investigated. It is established that the coating based on titanium and chromium has a single-phase structure (Ti,Cr)N with a face-centered cubic crystal lattice (FCC), and the coating based on chromium consists of chromium nitride CrN (FCC). It is shown that the Ti–Cr–N coating has greater hardness and toughness than the Cr–N coating. The Ti–Cr–N coating, due to its alloying with Ti atoms, has a higher adhesive strength as compared to the Cr–N coating. At the same time, in the Ti–Cr–N coating, the adhesive strength for a substrate made of Zr2.5%Nb alloy is ≈2 times greater than for a substrate based on steel 12X18H10, which may be associated with the formation of solid solutions between Ti and Zr elements. It is shown that on the contrary, the Cr–N coating can withstand heavy loads before tearing from a substrate based on steel 12X18H10T than from that based on a Zr2.5%Nb alloy. On the basis of the obtained data, one can say about the positive effect on the mechanical properties of titanium additive in the chromium-based coating composition.