The aim of this study was to obtain a stable sunflower oil-in-water (O/W) Pickering emulsion stabilized by chitosan (CS)-stearic acid (SA) nanogels and to compare the oxidative stability of the sunflower Pickering emulsion stabilized by CS-SA nanogels with sunflower oil emulsion stabilized by Tween 80. The results of the scanning electron microscopy revealed that by increasing the SA to CS ratio, the uniformity of particles was increased. Also, the results showed that the emulsions with pH of 8, SA to CS ratio of 0.5:1, and oil-to-nanogel ratio of 20:1 had the highest stability and minimum droplet size. In the following, the oxidative stability of the most favorable Pickering emulsion and the Tween 80-stabilized emulsion was evaluated and compared using the peroxide and thiobarbituric acid tests. The findings implied that the O/W emulsion stabilized by CS-SA nanogels had a higher oxidative stability than the O/W emulsion stabilized by Tween 80.