Bring a large pot of lightly salted water to a boil. Add linguini pasta, and cook for 8-10 mins, 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, sauté chicken in butter until no longer pink and juices run clear, about 5 to 7 minutes. Add green, red pepper, and mushrooms (sliced) and onion powder, cook 2-3 minutes. Reduce heat, stir in heavy cream. Season the sauce with basil, lemon pepper, salt, garlic powder, and ground black pepper, and heat through. *If it is too runny for your taste mix some corn starch (1-2 Tbls) and cold water (1/4-1/2 cup) together. Add to the sauce, stir and bring to a boil.
In a large bowl, toss linguini with sauce. Sprinkle with grated Parmesan cheese.