Preheat oven to 375°. Cook shells according to package directions for al dente; drain. Toss with oil; spread in an even layer on a baking sheet., For filling, toss chicken with Italian seasoning, 1/2 teaspoon salt and 1/4 teaspoon pepper. In a large skillet, heat oil over medium-high heat; saute chicken just until lightly browned, about 2 minutes. Reduce heat to medium; stir in butter until melted. Stir in bread crumbs; cook until crumbs are slightly toasted, 2-3 minutes, stirring occasionally. Cool slightly., In a large bowl, mix cheeses, milk, parsley and the remaining salt and pepper. Fold in chicken., Spread 2 cups pasta sauce into a greased 13x9-in. baking dish. Fill each shell with 2-1/2 tablespoons cheese mixture; place over sauce. Top with remaining sauce and cheeses (dish will be full)., Cover with greased foil; bake 30 minutes. Uncover; bake until heated through, 10-15 minutes.