We uncover a universal mechanism for realizing layer-locked topological phases. Guided by it, we investigate the realization of layer-locked chiral topological superconductivity-the superconducting analogue of the quantum anomalous layer Hall effect-in a nonsymmorphic bilayer antiferromagnetic system with s-wave pairing. We identify three distinct gate-tunable topological phases and establish a direct correspondence between the nearly quantized layer-resolved Chern numbers and the layer-locking behavior of chiral Majorana edge states, vortex-core Majorana zero modes, and nearly quantized thermal Hall responses.