This paper presents computational study of non-stoichiometric nickel oxide in a 32-cell NiO system to model and validate localized heating effects due to nanosecond laser irradiation. Variation in Bandgap of NiO is studied as a function of varying concentrations of native defects ranging from 0 to 25%. It is observed that there is a slight increase in the bandgap from 3.8 eV for stiochiometric NiO to 3.86 eV for Ni-rich NiO and to 3.95 eV for O-rich NiO. It is hence deduced that the experimental laser irradiation leads to simultaneous reduction of Ni²⁺ ions and oxidation of NiO as the number of laser pulses increase. As well, a detailed study on the effects of doping nickel family elements, i.e. palladium (Pd) and platinum (Pt) in stoichiometric NiO is presented. A bandgap decrease from 3.8 eV for pure NiO to 2.5 eV for Pd-doping and 2 eV for Pt-doping for varying doping concentrations ranging from 0–25% Pd, Pt respectively is observed.