In this article, we propose a novel approach for dielectric nanograting fabrication by direct laser patterning. Possibilities of a well-controlled ultra-short laser recording of Ag-SiO₂ nanocomposite gratings and their optical properties are examined. The mechanisms of laser processing involve silver nanoparticle growth in nanoporous silica glass films and laser interference-based formation of a periodic grating-like nanorelief. It is shown that laser energy should stay below the surface ”grooves” formation threshold for laser-inscription of the interference-based grating. Otherwise, another periodic structure oriented parallel to the incident laser polarization appears to erase the interference pattern. The parameter windows required for the controlled fabrication of the obtained structures are determined. The required threshold decay with the number of applied laser pulses is explained by a similarity in the roles of the nanoparticle absorption and surface defect accumulation typically leading to such dependencies. The optical properties of the obtained gratings are shown to depend on the angle between the incidence plane and the grating direction. When these directions coincide, a signal enhancement with a period-dependent blue-shift is revealed in the diffuse scattering spectra. When these directions are perpendicular, the signal is less enhanced, and a red shift is observed. The observed results are promising in short laser fabrication of different optical components, such as reflective optical filters.