Add the cubed chicken and Cajun seasoning, cooking until the chicken is browned and cooked through, about 5–7 minutes. In the same skillet, add the diced onion, red sweet pepper, and minced garlic. Add the cream cheese to the skillet and stir until melted and combined. Pour in the heavy cream and chicken broth, stirring to create a smooth sauce. Return the cooked chicken to the skillet and add the drained pasta, mixing everything together.