Brown turkey and Italian sausage in a large skillet over medium heat, cooking and stirring until meat is crumbly and no longer pink, about 10 minutes. Add green and red bell peppers to meat; cook and stir until peppers are soft and excess liquid has evaporated, about 10 more minutes.
Mix diced tomatoes, chili beans, red beans in chili sauce, yellow and white corn, black beans, chopped green chiles, barbeque sauce, cumin, chili powder, parsley, and red pepper flakes in a large soup pot. Place over medium heat, bring to a boil, and reduce heat to low. Simmer chili for 20 minutes. Stir turkey mixture into chili and simmer 15 more minutes to blend flavors.