Bring a large pot of salted water to a boil. Add the penne pasta and cook according to package instructions until al dente. Drain and set aside.
In a large skillet, heat the olive oil over medium-high heat.
Toss the chicken pieces with the Cajun seasoning until evenly coated.
Add the seasoned chicken to the skillet and cook for 5-7 minutes, stirring occasionally, until the chicken is cooked through and lightly browned. Remove the chicken from the skillet and set aside.
In the same skillet, add the sliced red bell pepper, green bell pepper, and yellow onion. Cook for 4-5 minutes until the vegetables are softened.
Add the minced garlic to the skillet and cook for 1 minute until fragrant.
Pour in the heavy cream and chicken broth, stirring to combine.
Add the grated Parmesan cheese, smoked paprika, and cayenne pepper. Stir well and bring the sauce to a simmer.
Season the sauce with salt and freshly ground black pepper to taste.
Return the cooked chicken to the skillet and stir to coat with the sauce.
Add the cooked penne pasta to the skillet and toss everything together until the pasta is evenly coated with the creamy Cajun sauce.
Cook for an additional 2-3 minutes to heat through.
Remove from heat and sprinkle with chopped fresh parsley before serving.