Background and Purpose In the present work, chitosan is furnished with tin dioxide (CsSnO2) nanoparticles (NPs) synthesized using the green route using Moringa oleifera(M. oleifera) flower extract.Methods These preparation methods are low-cost, easily reproducible, nontoxic, and eco-friendly. X-ray diffraction (XRD), dynamic light scattering (DLS), field emission scanning electron microscope (FESEM), energy dispersive X-ray, Fourier-transform infrared spectroscopy (FT-IR), and photoluminescence (PL) analysis were used to learn more about the CsSnO2NPs. The antibacterial property of CsSnO2NPs was assessed by the disc diffusion method against various pathogens. The MTT assay was done to assess the cytotoxicity of CsSnO2NPs in MCF-7 cells. The expressions of the apoptotic proteins were examined using assay kits.Results XRD results demonstrated that the formulated CsSnO2NPs exhibit a tetragonal structure. From the FT-IR spectra, the Sn–O stretching peak was observed at 579 cm–1. A FESEM image shows that the CsSnO2NPs were formed into a spherical structure. Surface defects, such as tin and oxygen vacancies, are visible in the PL spectra, and the average particle size of CsSnO2NPs is 32 nm. Thus, surface defects are essential parameters for biocidal properties. The antimicrobial property of CsSnO2NPs and amoxicillin was investigated against bacteria and human fungal pathogens. CsSnO2NPs exhibit similar antimicrobial properties as compared to amoxicillin. Also, the dosage of CsSnO2NPs elevated their antimicrobial activity. The anticancer property of the green-synthesized CsSnO2NPs against MCF-7 cells was further analyzed to study their ability to cytotoxicity and apoptosis induction, like caspase-3, -8, and -9 activation.Conclusion The study’s outcome revealed that the green synthesized CsSnO2NPs are an outstanding candidate for cancer therapy.