In same skillet, add remaining 2 teaspoons vegetable oil; heat over medium heat. Add sweet potatoes, bell pepper and green onions; cover and cook 6 to 7 minutes, stirring occasionally, until vegetables are crisp-tender. Add pea pods, carrots and chicken; cover and cook 2 minutes. Push chicken and vegetables to edges of skillet; add garlic and gingerroot in center of skillet. Cook 1 to 2 minutes or until fragrant. Stir in soy sauce, brown sugar, remaining teaspoon of sesame oil and the pepper flakes. Cook 1 to 2 minutes, stirring frequently, until completely heated through. Garnish with sesame seed.