Chop the chicken into 1-inch chunks. Place in a zip-top bag with 1 tablespoon of olive oil and cajun seasoning. Mix well to coat. Let marinate while you chop the bell peppers.
Chop the bell peppers into bite-sized pieces.
Cook the fettuccini according to package instructions. Drain and set aside.
Heat remaining olive oil in a large skillet over high heat. Add the marinated chicken and cook in a single layer.
Cook for 3-4 minutes, then flip and cook for another 2 minutes. Add the pressed garlic and cook for 1 additional minute or until the chicken is cooked through.
Remove the chicken and set aside. In the same skillet, melt butter with remaining cajun seasoning.
Add heavy cream, cream cheese, and parmesan cheese. Whisk until melted and bring to a boil for 1 minute.
Return the chicken and bell peppers to the skillet, tossing with the sauce.
Add the drained pasta and toss until coated. Serve immediately, garnished with green onions.
