Meanwhile, melt butter in a large Dutch oven over medium-high heat. Add onion and bell pepper, and sauté 5 minutes or until tender. Stir in tomatoes and green chiles and prepared cheese product; cook, stirring constantly, 2 minutes or until cheese melts. Stir in chicken, next 4 ingredients, and hot cooked pasta until blended. Spoon mixture into a lightly greased 10-inch cast-iron skillet or 11- x 7-inch baking dish; sprinkle with shredded Cheddar cheese.