Polymer-blend-based nanocomposites incorporating carbon nanomaterials hold significant potential for microwave absorption materials (MAM) applications. This study investigates the microwave absorption response of hybrid nanocomposites composed of multiwalled carbon nanotubes (MWCNT) and nanographite, prepared using industrial-like melt-mixing masterbatch strategies in a polycarbonate/acrylonitrile-butadiene-styrene copolymer (PC/ABS) blend matrix with varying blend ratios (100/0, 80/20, 60/40, 50/50, 40/60, 20/80, and 0/100) and a constant filler content (2 wt % MWCNT and 2 wt % nanographite). Furthermore, the PC/ABS (40/60) blend-based nanocomposite was prepared with the addition of a compatibilizer, 5 wt % of maleic anhydride grafted ABS (ABS-