Auger and core-level photoemission from thin NiO films deposited on an MgO(100) substrate are studied by XAES and XPS, respectively. A detailed analysis of the Ni 2p 3 / 2 main line and Ni L 3 VV for submonolayer coverages allows us to give a new assignement to the different spectral features. In terms of a cluster model, the high binding-energy component of the Ni 2p 3 / 2 main line is assigned to the c3d 9 L (here L stands for the O 2p ligand hole) final state configuration, and the low binding-energy one to the c3d 9 3d, where 3d denotes a hole localized in the Ni 3d orbitals. The intensities of higher- and lower-energy components of the Ni 2p 3 / 2 main line depend on the number of ions (oxygen anions and nickel cations) surrounding emitting nickel rather on their chemical state. Non-local effects are also observed in the Ni LVV Auger spectra. At low coverages (less than 0.5 ML), a single line at 841 eV kinetic energy is observed. The higher-energy component of Ni LVV spectra at 846 eV is related to the presence of Ni cations as next-nearestest neighbors.