The mass production and commercialization of integrated photonics have been slowed down by the high cost of packaging its optical interfaces. We show a plug-and-play connector between a fiber and a nanophotonic waveguide consisting of a 3D polymer structure with a fiber entrance port that simultaneously achieves mechanical and optical passive alignment with tolerance beyond ±10 μm to the fiber input position. We take advantage of a mechanical and optical co-design, analogous to commercial fiber-to-fiber connectors. We fabricate the plug-and-play couplers using 3D nanoprinting directly on foundry fabricated diffraction grating couplers. We measure an average of only 0.05 dB excess coupling loss between a single mode fiber and a high confinement silicon waveguide in addition to the inherent grating coupler loss. Our coupling platform offers a passive plug-and-play solution for scalable integrated photonics fiber-chip packaging.