In a medium bowl, combine the cornstarch with the water. Whisk in the brown sugar, soy sauce, honey, ginger, and garlic powder.
Add the sauce to a small sauce pan and bring the sauce to a simmer over medium-high heat. Reduce the heat to medium and cook until the chicken is cooked through and the sauce has thickened enough to coat the back of a spoon, about 5 minutes. The sauce will continue to thicken as it cools.