Broil bell pepper and chile peppers on an aluminum foil-lined baking sheet 5 inches from heat about 5 minutes on each side or until peppers look blistered.
Place peppers in a heavy-duty zip-top plastic bag; seal and let stand 10 minutes to loosen skins. Peel peppers; remove and discard seeds. Coarsely chop peppers.
Bring chopped roasted peppers, chicken broth, and next 5 ingredients to a boil in a Dutch oven over medium heat. Reduce heat, and simmer 15 minutes or until potato is tender.
Melt butter in a heavy saucepan over low heat; whisk in flour and next 3 ingredients until smooth. Cook, whisking constantly, 1 minute. Gradually whisk in half-and-half.
Stir white sauce and milk into chicken broth mixture; cook over medium heat 8 to 10 minutes or until thickened and bubbly. Sprinkle each serving evenly with cheese, bacon, and green onions.