Preheat oven to 350° F. Spray a 9×9 inch baking pan with non-stick spray.
Combine soy sauce, ½ cup water, brown sugar, ginger and garlic in a small sauce. Bring to a boil over medium heat and cook for one minute once boiling.
Meanwhile, stir together the corn starch and 2 tablespoons of water in a separate dish until smooth. Once sauce is boiling, add mixture to the saucepan and stir to combine. Cook until the sauce just starts to thicken then remove from heat. Add 1/2 cup sauce to the shredded chicken.
In a large skillet with oil, saute the veggies until crisp tender about 5 minutes. Pour over 1/2 cup of the sauce. Place the chicken, veggies and rice in the prepared pan. Add the cooked rice to the casserole dish. Add most of the remaining sauce, reserving a bit to drizzle over the top when serving. Gently toss everything together until combined. Bake covered for 20 minutes or until everything is heated through. Remove from oven and let stand 5 minutes before serving. Drizzle each serving with remaining sauce.