Integrating nanoparticle (NP)-based electrically conductive elements inside additive manufactured parts has a high potential for next-generation smart structures. We investigate, a novel technique in which mixed silver nanowires (NW) and nanospheres (NS) are printed as interconnects and sintered using out-of-chamber Intense Pulsed Light (IPL) sintering inside 3D printed thermally sensitive Acrylonitrile Butadiene Styrene (ABS) and Polylactide (PLA) polymer structures. The inclusion of NWs with the typically used NSs is found to realize dual advantages of no thermal damage of the polymers and a that is much lesser resistivity than the state-of-the-art (13.1 μΩ-cm) only 8X higher than bulk silver. Resistivity decreases with a greater percentage of NW content. On the contrary, the NS-only sample didn’t show any conductivity even after IPL sintering because the wavy feature of 3D printed surface didn’t allow NSs to bond. Even though a greater reduction of resistivity is achieved due to IPL, sintering temperature was below 97°C and maximum sintering time reported is 0.75 seconds which cumulatively resulted in damage-free substrates. When dynamic resistivity is analyzed during polymer overprinting on interconnects, four different resistance trends are seen and explained here. Surprisingly, overprinting on the post-IPL interconnect to fully embed the interconnect inside the structure causes a further resistivity reduction to 11.8 μΩ-cm as well.