To make the sauce, in a small bowl or measuring cup, whisk together the orange juice, soy sauce, minced garlic, sugar, and corn starch until well blended.

Heat the oil in a large skillet over medium high heat. Add the chicken to the skillet and cook, stirring frequently, until browned and cooked through. Remove the chicken from the skillet to a plate.

Add the broccoli, green onions, and water to the skillet. Cover and cook 2-3 minutes, until the broccoli is bright green and slightly softened, but still crisp. Add the chicken back into the skillet, and pour the sauce over the chicken and broccoli. Cook, stirring frequently, until the sauce has thickened. Remove from heat and serve immediately.