Multi-orbital/band electronic structure and orbital-dependent electron correlations critically shape emergent electronic states in correlated materials. Bulk FeSe exemplifies this through its enigmatic nematic phase, whose microscopic mechanism remains an outstanding question. Here, we perform comprehensive 57Fe and 77Se nuclear magnetic resonance (NMR) study on the evolution of the nematicity of bulk FeSe under hydrostatic pressure. At low pressures, alongside the nematicity involving on-site 3dxz/3dyz orbital polarization, a distinct non-local \({d}_{{xy}}\) nematicity emerges, indicating anisotropic intersite hopping of 3dxy orbital electrons. With increasing pressure, while the on-site 3dxz/3dyz orbital polarization is gradually suppressed, the Lifshitz transition of the 3dxy orbital hole pocket causes the \({d}_{{xy}}\) nematicity transforms into a spin-driven Ising-type nematicity above a characteristic pressure. This Fermi-surface crossover also influences the superconducting transition temperature \({T}_{{\rm{c}}}\) , signifying the pivotal role of the more-correlated 3dxy orbital in Cooper pairing at high pressures. Our results establish the orbital-selective nature of nematicity in FeSe and its nontrivial tunability via hydrostatic pressure. We demonstrate that nematicity serves as a sensitive indicator of the underlying electronic structure and interactions in correlated electron systems.
