Place chicken breasts in large resealable plastic bag; add 2 tablespoons of the dressing. Seal and marinate at room temperature for 15 minutes.
In a large saute pan, heat 1 tablespoon olive oil over medium-high heat. Add peppers and cook 5 minutes or until peppers are softened. Remove and reserve.
Stir together 3 tablespoons of the dressing, 1/4 cup of the cream and enough water to make 1-1/2 cups. Place mashed potatoes (2-2/3 cups) in microwave-safe bowl; stir in dressing mixture. Microwave on HIGH 6 to 8 minutes, stirring once. Cover until ready to serve.
Meanwhile, remove chicken from bag. Add to pan; sprinkle with 1/4 teaspoon salt. Saute 4 minutes on one side. Turn and cook another 4 minutes, or until browned. Reduce heat to medium-low. Add peppers back to skillet along with remaining dressing and cream.
Cook another 2 minutes or until chicken is cooked through and registers 160°F on an instant-read thermometer. Stir mashed potatoes and reheat if necessary; serve with chicken and peppers.