Season the chicken pieces evenly with the Cajun seasoning.
Heat the olive oil in a large skillet over medium-high heat. Add the chicken and cook until browned and cooked through, about 5-7 minutes. Remove the chicken from the skillet and set aside.
Reduce the heat to medium. Add the chopped onion to the same skillet and cook until softened, about 3 minutes. Add the minced garlic and cook for 1 minute more until fragrant.
Pour in the chicken broth and scrape up any browned bits from the bottom of the skillet. Let the broth simmer and reduce slightly for 2 minutes.
Stir in the heavy cream and Italian herbs. Bring the mixture to a gentle simmer.
Reduce the heat to low. Stir in the Parmesan cheese until the sauce is smooth and slightly thickened.
Return the cooked chicken to the skillet. Stir to coat the chicken in the cream sauce. Cook for 1-2 minutes until the chicken is heated through.
Season with black pepper. Garnish with fresh parsley before serving.
Notes
If you do not have pre-made Cajun seasoning, mix paprika, cayenne pepper, garlic powder, onion powder, dried oregano, and salt to create your own blend.
For a thicker sauce, let the broth reduce longer before adding the cream, or simmer the final sauce uncovered for a few extra minutes.
You can substitute half-and-half for heavy cream, but the sauce will be slightly thinner.