ABSTRACT Polymerization‐induced self‐assembly (PISA) has become a scalable route to block copolymer nanoparticles with tunable morphologies, but most established PISA formulations focus on linear architectures. This review surveys recent progress in extending PISA to nonlinear polymers—highlighting how polymer topology reshapes nucleation, packing, interfacial curvature, and ultimately nanoparticle morphology—while also positioning PISA as a practical method for synthesizing architecturally complex macromolecules. Key advances are summarized across star, graft, bottlebrush, branched, and cyclic polymers. Finally, we also discuss future opportunities of PISA of nonlinear polymers that may provide some inspirations for researcher in this area.