A tin oxide (SnO2) nanostructure was prepared using Matricaria recutita leaf extract to investigate its anticancer activity against SK-MEL-28 cells. The tetragonal crystal structure of tin oxide nanoparticles with an average crystal size of 27 nm was confirmed by X-ray diffraction (XRD) analysis. The tetragonal crystal structure of the tin oxide nanoparticles, with an average crystallite size of 27 nm, was confirmed by XRD an absorbance peak at 365 nm was identified by UV–visible spectroscopy analysis as belonging to the bio-mediated synthesis of SnO2 nanoparticles. The SnO2 NPs are capped and stabilized with diverse functional groups derived from bioactive molecules, including aldehydes, benzene rings, amines, alcohols, and carbonyl stretch protein molecules. Fourier transform infrared spectroscopy (FTIR) analysis validated the presence of these capping and stabilizing chemical bonds. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed the cauliflower-shaped morphology of the SnO2 nanoparticles with an average particle size of 28 nm. The antimicrobial activity of both prepared and encapsulated samples confirmed their biological activities. Furthermore, both prepared and encapsulated tin oxide samples exhibited excellent anticancer activity against SK-MEL-28 human cancer cells. The present study introduces a reliable and uncomplicated approach to produce SnO2 nanoparticles and demonstrates their effectiveness in various applications, including cancer therapy, drug administration, and disinfectant.