Bake the chicken according to the package instructions.
Meanwhile, prepare the sauce. In a large measuring cup (or small bowl), whisk together the soy sauce, ketchup, brown sugar, honey, Thai sweet chili sauce, sesame oil, rice vinegar, cornstarch, and garlic powder.
When there are about 5 minutes left in the chicken’s cooking time, heat a large skillet or wok over medium-high heat. Add the sauce mixture to the skillet; bring to a simmer. Cook, whisking frequently, for 3-4 minutes, until the sauce thickens. Remove from the heat, add the baked chicken to the pan, and toss to coat with the sauce.
Garnish with green onions and sesame seeds. Serve with rice, if desired.