1Preheat the oven to 375 degrees F (190 degrees C).
2Toss together chicken, onion powder, 2 tablespoons Sriracha, 2 tablespoons soy sauce, and 1 tablespoon garlic in a large bowl. Sprinkle with flour until completely coated.
3Heat oil in a large cast-iron skillet over medium-high heat until shimmering. Working in 2 batches, add chicken in an even layer; cook, undisturbed, until browned on both sides, about 6 minutes total, flipping halfway through. Transfer chicken to a plate. Do not wipe skillet clean. Repeat with remaining chicken.
4Reduce heat to medium and stir in rice, 2 tablespoons sweet chili sauce, 1 1/2 teaspoons rice vinegar, remaining 1 tablespoon soy sauce, and remaining 1 tablespoon garlic. Cook, stirring occasionally, until fragrant and rice is toasted, about 2 minutes.
5Stir in broth and bring to a boil over medium-high. Remove from heat and top evenly with chicken. Cover with a tight-fitting lid or aluminum foil.
6Bake in the preheated oven until rice is tender and cooked through, 22 to 25 minutes.
7Whisk together mayonnaise, remaining 1/4 cup sweet chili sauce, 2 tablespoons Sriracha, and 1 1/2 teaspoons rice vinegar until smooth.
8Drizzle casserole with bang bang sauce, garnish with scallions and sesame seeds.
Ingredients
2 pounds skinless boneless chicken thigh, cut into bite-size pieces