The electrocatalytic nitric oxide reduction reaction (NORR) has attracted significant attention as an eco-friendly alternative to conventional Haber-Bosch process for producing ammonia (NH3). However, the poor selectivity to NH3 and low catalyst stability under harsh conditions are great challenges in NORR. Herein, core-shell structure of nickel nanoparticles enclosed with nitrogen-doped carbon layer (Ni@NC) electrocatalyst derived from covalent organic frameworks is employed for high performance in NORR. The Ni@NC-700 achieved the highest FENH3 of 82.94% with an NH3 yield rate of 19.00 µmol cm-2 h-1 at 0.16 V (vs. RHE) in a 0.1 M HClO4 electrolyte. Control experiments revealed that the nickel nanoparticles (Ni NPs) acted as active centers in Ni@NC for efficient production of NH3. The ideal carbon shell protecting of Ni NPs and high inherent catalytic TOF of Ni@NC-700 revealed a promising candidate for efficient NORR electrocatalyst. The stability test demonstrated the remarkable stability of Ni@NC. The Ni NPs were protected by carbon nanostructures resembling core-shell catalysts, preventing metal dissolution during rough electrolysis.