Nanoparticle-based fertilizers offer next-generation solutions for sustainably improving crop productivity and nutrient content. In this study, green synthesized hematite nanoparticles (Fe2O3 NPs), derived from Brassica nigra seed extract, were applied as a seed nano-priming treatment in rice (Oryza sativa). The Fe2O3 NPs were spherical (14.05 ± 6.96 nm), highly stable (-50mV), and characterized using standard techniques. Priming seeds with 50-150mg/L of Fe2O3 NPs enhanced germination, a-amylase activity, water uptake, and early growth. At 150 mg/L, shoot and root lengths increased by 41% and 109%,respectively, while grain yield rose by 126% and 1000-grain weight by 62%.Chlorophyll a and b levels increased by 62% and 85%, and grain iron content rose by 144% (16.67 mg/kg), contributing up to 21% of daily iron requirements for men. The hazard risk index remained below 1, indicating safe application. These results suggest that phytogenic Fe2O3 NPs are effective, eco-friendly Nano-fertilizers for improving rice yield and iron nutrition through a safe and sustainable approach.