1Cook and drain tortellini as directed on package.
2Meanwhile, in 3-quart saucepan, heat oil over medium-high heat. Cook chicken in oil, stirring frequently, until no longer pink in center. Remove chicken from saucepan; keep warm.
3In same saucepan, melt butter over medium-high heat. Cook bell pepper, shallots and garlic in butter, stirring frequently, until bell pepper is crisp-tender. Stir in flour and pepper. Cook over medium heat, stirring constantly, until mixture is bubbly; remove from heat. Stir in milk. Heat to boiling, stirring constantly. Boil and stir 1 minute; remove from heat.
4Stir in mozzarella and Swiss cheeses until melted. Stir in tortellini and chicken until coated. Sprinkle with Parmesan cheese.