Preheat oven to 350 F.
Blend together sauce ingredients and set aside.
Cook pasta according to package directions; drain.
Stir together chicken and next six ingredients. If not using large shells, cut pasta shells lengthwise through the side.
Spoon about 1/4 to 1/2 cup chicken mixture into each shell, gently pressing cut sides together. Place filled side down in two lightly greased 11x7-inch baking dishes.
Pour roasted red pepper sauce evenly over pasta. Bake uncovered for 25-30 minutes.