Sprinkle chicken with salt and pepper; coat in flour. Melt butter in 12-inch nonstick skillet over medium-high heat. Add chicken and cook 4 minutes per side, until golden; set aside.
Add pancetta and onion to same skillet; cook, stirring frequently until onion is golden and pancetta is crisp, 3 minutes. Add spinach and mushrooms; cook 3 minutes , until spinach is wilted. Add Marsala and bring to a boil. Stir in cream, marinara sauce and artichokes. Reduce heat and simmer 7 minutes.
Return chicken to skillet; cover with sauce and vegetables and cook 2 minutes more, until heated through. Stir in tortellini. Divide chicken, sauce and pasta among 4 serving plates.