Abstract <p>High-entropy nitrides have the potential to enhance mechanical properties and high-temperature stability compared to mono- or binary nitrides. They are particularly promising for applications requiring high temperatures and hardness. Here, we report on a facile one-step route for the fabrication of a high-entropy nitride powder (TiZrHfNbTa)N_x. The novel approach employs the mechanical alloying of metal powders within a planetary ball mill under elevated nitrogen pressure. Ball milling a mixture of five transition metals under a nitrogen pressure of 0.6 MPa for 60–90 min leads to the formation of a high-entropy nitride with a rock-salt crystal structure. The as-prepared powder exhibits nanoscale crystallites and a uniform distribution of metals within the cationic sublattice. The total nitrogen content of the synthesized powder is 8.9 wt %, indicating the formation of a non-stoichiometric high-entropy nitride (TiZrHfNbTa)N_0.83. The scalable technological approach developed in the current study could also be used to produce other multielement nitrides, thereby expanding the range of nitride ceramics available.</p>