Nano building blocks (NBBs) decorated with well-defined polymer tethers have emerged as a promising type of building blocks for constructing hierarchical materials through programmable self-assembly. We present a general and facile strategy for preparing hybrid NBBs composed of silica-like heads decorated with well-defined polymer tethers by the self-collapse of polymer single chains. Using amphiphilic block copolymers (BCPs) of poly(ethylene oxide)-block-[poly(methyl methacrylate)-co-poly(3-(trimethoxysilyl)propyl methacrylate)] (PEO-b-P(MMA-co-TMSPMA)), the intramolecular hydrolysis and polycondensation of silane moieties led to the formation of hybrid NBBs with silica-like heads and PEO tethers. The formation of hybrid NBBs was carefully characterized by gel permeation chromatography, nuclear magnetic resonance spectroscopy, transmission electron microscopy, and static/dynamic light scattering. In a mixed solvent of THF/water, amphiphilic NBBs could assemble into spherical micelles, vesicles, and large compound micelles, depending on the size of silica heads and the initial concentrations. The intramolecular cross-linking of P(MMA-co-TMSPMA) blocks significantly altered the assembly behavior of linear BCPs. The rigid hydrophobic heads of NBBs could not be stretched/compressed, and the self-assembly of NBBs behaved surfactant-like. Furthermore, we observed that the mismatched dimensions of NBBs and linear BCPs would give rise to the formation of unprecedented phase-separated bilayer vesicles when coassembling two amphiphiles. Our study of NBBs may bridge the study of nanoparticles and polymeric building blocks and offer new opportunities to synthesize hybrid NBBs with controlled functionalities for use in novel functional materials and devices.