We propose a novel, to the best of our knowledge, approach for engineering vector flat bands-degenerate dispersionless bands supporting dual-polarization electromagnetic modes-through precision structural design of moiré photonic crystals. This platform enables the generation of highly uniform superchiral fields under wide-angle illumination, achieving field enhancements exceeding 100-fold compared to conventional circularly polarized light across a broad angular spectrum. This broadband angular tolerance eliminates the strict alignment requirements in chiral molecular detection systems, which may possess important applications in the field of ultrasensitive detection of molecular chirality.