1. Preheat broiler.
2. Cut bell peppers in half lengthwise; discard seeds and membranes. Place pepper halves, skin sides up, on a foil-lined baking sheet; flatten with hand. Broil 15 minutes or until blackened. Place in a heavy-duty zip-top plastic bag; seal bag. Let stand 10 minutes. Peel and cut into strips.
3. Heat a 6-quart Dutch oven over medium-high heat. Add 1 tablespoon olive oil to pan; swirl to coat. Add chicken to pan; cook 6 minutes, turning to brown on all sides. Remove chicken from pan. Add 1 tablespoon olive oil to pan. Add onion and next 4 ingredients (through garlic). Cook over medium heat 4 minutes or until vegetables are tender, stirring occasionally.
4. Add sherry to pan; cook until liquid evaporates, scraping pan to loosen browned bits. Stir in tomatoes, salt, and pepper. Bring to a boil; reduce heat and simmer, uncovered, 20 minutes, stirring occasionally. While sauce simmers, cook pasta according to package directions, omitting salt and fat; drain.
5. Add roasted bell pepper, chicken, and, if desired, olives to tomato mixture. Bring to a simmer. Stir in cream; cook 2 minutes or just until thoroughly heated, stirring occasionally. Add pasta, tossing well. Sprinkle with Parmesan cheese.