Mix flour, garlic powder, salt and pepper in a shallow dish. Dredge chicken pieces evenly with flour.
Heat 3 tablespoons of the oil in a 4-5 quart Dutch oven over medium high heat. Add chicken; cook and stir 8-10 minutes or until pieces are separated and lightly browned. Remove chicken from Dutch oven. Cover and set aside.
Heat remaining oil in same pot. Add mushrooms, onion, garlic, green pepper and yellow pepper. Cook and stir for 6-8 minutes on medium high heat until crisp/tender. Add diced tomatoes, tomato puree and Italian seasoning. Bring to a simmer, stirring frequently.
Return chicken to Dutch oven with the chicken broth and cook for 8-10 minutes or until chieck is cooked through. Add the cooked pasta. Cook and simmer for 5 minutes or until pasta is heated through.