PREPARE pasta according to package directions, reserving ¾ cup of cooking water.
PLACE tomatoes and pesto in food processor. Process until combined.
PLACE tomato mixture and reserved cooking water in medium saucepan. Bring to a boil. Stir in bell pepper and chicken. Remove from heat. Season with salt, ground black pepper and a squeeze of lemon. Toss with cooked pasta. Top with cheese and parsley.