Heat oil in a stock pot over high heat. Add in onions, garlic, green pepper, mushrooms and tomatoes. Saute until vegetables are tender, about 4 minutes.
Add chicken and sauté until golden brown. Add basil, black pepper, parsley and stir together. Turn down heat and allow to simmer.
Cook spaghetti and a separate pot according to directions on package. Serve one cup of spaghetti with one cup of mixture for each serving.