Using green tomato extract, a green approach was used to synthesize manganese oxide nanoparticles (MnO 2 NPs). The synthesis of MnO 2 NPs was (20.93−36.85 nm) confirmed by energy-dispersive X-ray (EDX), scanning and transmission electron microscopy (SEM and TEM), Fourier transform infrared spectroscopy (FTIR), and UV−visible spectroscopy (UV−vis) analyses. One hundred fifty-day-old Arbor Acres broiler chicks were randomly divided into five groups. The control group received a diet containing 60 mg Mn/kg (100% NRC broiler recommendation). The other four groups received different levels of Mn from both bulk MnO 2 and green synthesized MnO 2 NPs, ranging from 66 to 72 mg/kg (110% and 120% of the standard level). Each group comprised 30 birds, in three replicates of 10 birds each. Generally, the study's results indicate that incorporating MnO 2 NPs as a feed additive had no negative effects on broiler chick growth, antioxidant status, and overall physiological responses. The addition of MnO 2 NPs, whether at 66 or 72 mg/kg, led to enhanced superoxide dismutase (SOD) activity in both serum and liver tissues of the broiler chicks. Notably, the 72 mg MnO 2 NPs group displayed significantly higher SOD activity compared to the other groups. The study was further justified through docking. High throughput targeted docking was performed for proteins GHS, GST, and SOD with MnO 2 . SOD showed an effective binding affinity of −2.3 kcal/mol. This research sheds light on the potential of MnO 2 NPs as a safe and effective feed additive for broiler chicks. Further studies are required to explore the underlying mechanisms and long-term effects of incorporating MnO 2 NPs into broiler feed, to optimize broiler production and promote its welfare.