We investigated the magnetic properties of the Heusler alloy NiMnSn grown on thermally oxidized Si (100) by performing magnetic hysteresis measurements using the Polar Magneto-Optical Kerr Effect (PMOKE) technique. For a thickness of 30 nm, the NiMnSn alloy demonstrates out-of-plane magnetic anisotropy. We observed clear exchange bias, which we attribute to the exchange coupling between the spin glass and ferromagnetic phases. Our study also revealed that the growth of a 1 nm thick Heusler alloy NiMnSn layer on a cobalt layer with perpendicular anisotropy enhances the perpendicular magnetic anisotropy. However, we observed an antagonistic effect with thicker Heusler layers, resulting in a loss of perpendicular anisotropy and the appearance of an exchange bias (EB).