Bring a large pot of lightly salted water to a boil.
Add pasta and cook for 8 to 10 minutes or until al dente; drain.
Place the chicken and the Cajun seasoning in a plastic bag. Shake to coat. In a large skillet over medium heat, saute the chicken in butter or margarine until almost tender (5 to 7 minutes).
Add the red bell pepper, green bell pepper, mushrooms and green onion.
Saute and stir for 2 to 3 minutes. Reduce heat.
Add the cream, basil, lemon pepper, salt, garlic powder and ground black pepper.