Heat water for pasta in a large pan. Cook pasta according to package directions. Set aside.
Combine sliced chicken and cajun seasoning in a bowl or large plastic bag and combine until all the pieces are coated.
Heat olive oil in a large sauté pan over medium heat. Add in mushrooms and bell peppers. Cook until crisp-tender. Add in cajun-coated chicken pieces. Stir until no longer pink.
Add green onions, salt, pepper, garlic powder and half & half. Don't boil, but lightly simmer on low-medium heat until half & half has thickened a bit. Add in basil.
Pour pasta into chicken mixture and stir to combine. Top with extra fresh basil or green onions and parmesan. Serve and enjoy!