In a large skillet, melt butter over medium heat. Add pancetta and onion, and cook 10 minutes, or until pancetta is crispy and onion is soft. Remove pancetta and onion from pan with slotted spoon, keeping as much butter in pan as possible; set pancetta and onion aside.
Lightly pound chicken to 1/4-inch thickness. Cut into 2-inch pieces.
In a shallow dish, combine flour and salt. Dredge chicken pieces in flour mixture, and cook in pan drippings over medium heat 4 to 5 minutes, or until chicken is lightly browned. Using slotted spoon, remove chicken from pan, and set aside.
Add tomato sauce, vodka, Worcestershire sauce, salt, and red pepper flakes to pan drippings, stirring well. Cook over medium heat until bubbly.
Stir in cream, and cook until thickened.
Return pancetta, onion and chicken to cream mixture. Cook until heated through.
Toss chicken cream mixture with hot cooked pasta. Serve with grated Parmesan cheese.