COOK potatoes in boiling water in large covered saucepan 15 min. or until tender. Meanwhile, combine dressing, mustard and dill; set aside.
HEAT oil in large skillet on medium-high heat. Add chicken; cook and stir 3 to 4 min. or until chicken is cooked through. Place in large bowl.
DRAIN potatoes. Add to chicken along with the peppers; mix lightly. Add dressing mixture; toss gently to coat.