The laser-induced damage threshold of optical coatings in the nanosecond pulse regime is limited by the electric field distribution and existing defects, such as nanometer-sized particles or voids. Furthermore, the determination of the LIDT is strongly sensitive to the laser beam diameter, which is often explained by the lack of coverage of the existing defect ensemble for small spot sizes. In a previous study, an unexpected decrease in LIDT of high-reflecting mirrors was observed, when large beam diameters were applied on mirrors designed for a large angle of incidence. This phenomenon did not occur under normal incidence and was verified to be independent of the damage initiating defects in tests with gold nanoparticles, which could indicate a macroscopic interaction between nanometer-sized defects. This contribution presents a theoretical analysis of a possible interaction between the electric field of the incident laser pulse and the proportion of the electric field that is coupled into the thin film due to scattering by spherical nanoparticles. The studied parameters include the particle size, defect distributions, material combinations and the angle of incidence.