Preheat oven to 350°F (175°C). Grease a 9x13-inch baking dish with oil or non-stick spray.

In a small saucepan, combine soy sauce, honey, rice vinegar, minced garlic, and grated ginger. Heat over medium heat and bring to a gentle simmer, stirring occasionally.

For thicker sauce, dissolve cornstarch in 1 tablespoon cold water and stir into simmering sauce. Let simmer for 2-3 minutes until thickened and coating the back of a spoon. Remove from heat and set aside.

In a large skillet, heat sesame oil over medium heat. Add cubed chicken and cook, stirring occasionally, until browned and cooked through, about 6-8 minutes.

Spread cooked rice evenly across the bottom of prepared baking dish.

Evenly distribute cooked chicken, broccoli florets, sliced carrots, and red bell pepper over rice layer.

Pour prepared teriyaki sauce evenly across entire casserole, ensuring all ingredients are coated.

Cover dish with aluminum foil and bake for 25-30 minutes, or until vegetables are tender but still vibrant in color.

Remove from oven and let rest for 5 minutes. Remove foil and garnish with sesame seeds and chopped green onions if desired. Serve hot.