Season the chicken with a pinch of salt and pepper. Heat oil in a skillet over medium-high heat. Add chicken and cook until browned and cooked through, about 5–7 minutes. Don’t rush—let it get a little caramelized color.
While the chicken cooks, whisk together sweet chili sauce, soy sauce, rice vinegar, garlic, and ginger in a small bowl.
Pour the sauce into the skillet with the chicken. Stir to coat evenly. If you want a thicker glaze, whisk cornstarch with a splash of water and add it to the pan, simmering until glossy.
Let everything simmer for 2–3 minutes until the sauce thickens and sticks to the chicken. Taste and adjust salt if needed.
Turn off the heat, sprinkle with sesame seeds and green onions if you like a little green flair. Serve hot.