Supercrystalline nanocomposites (SCNCs) are a new category of hybrid materials that typically consist of inorganic nanoparticles, functionalized with organic ligands on their surface. and assembled into periodic structures. They have attracted growing attention thanks to their hierarchical architecture and intriguing functional properties (plasmonic, optoelectronic, biomedical). Understanding and tuning their mechanical properties is thus a crucial step to enable a broad set of applications. A key strategy towards strengthening, stiffening and hardening SCNCs has been found in crosslinking the organic ligands, a heat-induced step that shifts the interactions holding together the material building blocks from van der Waals to covalent bonds. So far, the mechanical behaviour of SCNCs has been partially assessed in terms of time-independent phenomena. However, time-dependent deformation is expected to play an important role, especially for their long-term serviceability, given the presence of organic constituents. Here, the time-dependent deformation behavior of ceramic-based SCNCs is investigated via nanoindentation. It emerges that both creep and its recovery occur in SCNCs, both with and without the crosslinking of the organic ligands, even though creep is less pronounced when crosslinking is present. Creep deformation does not completely recover even several weeks after nanoindentation, implying the presence of both viscoelasticity and viscoplasticity. The creep mechanism is further analyzed by adapting the classic models of crystalline materials to supercrystalline ones, through an analysis of stress exponent and activation volume. The large value of the stress exponent points at the occurrence of power-law breakdown, resulting from the localized high stresses induced by the Berkovich tip. A new creep mechanism is proposed for SCNCs to account for the extremely small activation volume (~10-5b3, b: modulus of Burgers vector), i.e. organic ligands-facilitated rearrangement of the materials’ nanoconstituents, achieved via the rearrangement of organic ligands in the sub-nm inter-particle spacings. A thorough analysis of thermal drift and nanoindentation mode effects is also presented.