Chitosan-based hydrogels with zinc oxide nanoparticles and phosphocreatine were developed as injectable 3D scaffolds for bone regeneration. Phosphocreatine in the hydrogel enables supramolecular bonding with ZnO nanoparticles and serves as a reservoir for the controlled release of Zn²⁺ ions. Freeze-dried CSMP-ZnO hydrogels have a porous structure with small openings in the pore walls, which was confirmed by scanning electron microscopy. The mechanical properties of the hydrogels were almost unchanged after the addition of ZnO nanoparticles. In vitro experiments showed that CSMP-ZnO hydrogel supports bone and blood vessel formation better than hydrogel without ZnO. Released Zn²⁺ ions increase collagen 1 expression and accelerate bone mineralization via the BMP2/SMAD signaling pathway. In vivo, high osteoblast proliferation and stable vasculature formation were observed in CSMP-ZnO hydrogels, as confirmed by immunofluorescence for RUNX2, COL-1 and CD31. The results show that this hydrogel is promising for bone regeneration and tissue engineering.