Single-chain polymer nanoparticles (SCNPs) are individual intrachain cross-linked polymer chains -typically with a size < 20 nm-which can be considered as emerging building blocks for bionanotechnology. Very recently, surfaces displaying molecular recognition motifs have been decorated with brushes of responsive SCNPs and transformed into a cross-linked polymeric monolayer, thus paving the way to controlled nanofilm formation around bioactive surfaces (e.g., virus capsids). In this work, the structural properties of brushes formed by topologically complex SCNPs on flat surfaces are investigated as a function of SCNP size and intrachain cross-linking degree. A detailed comparison is performed to the structural features displayed by brushes of other macromolecular architectures, thus revealing the tunable, unique properties of brushes comprising elastic SCNPs. Remarkably, this work paves the way to the potential design of brushes of SCNPs with drug delivery characteristics based on stimulus-mediated rupture of intrachain cross-links.