Bring a large pot of lightly salted water to a boil. Add linguini pasta, and cook for 8 to 10 minutes, or until al dente; drain.
Meanwhile, place chicken and Cajun seasoning in a bowl, and toss to coat.
In a large skillet over medium heat, saute chicken in butter until no longer pink and juices run clear, about 5 to 7 minutes. Add green and red bell peppers, sliced mushrooms and green onions; cook for 2 to 3 minutes. Reduce heat, and stir in heavy cream. Season the sauce with basil, lemon pepper, salt, garlic powder and ground black pepper, and heat through.
In a large bowl, toss linguini with sauce. Sprinkle with grated Parmesan cheese.