Preheat the oven to 375°F (190°C).
Cook the jumbo pasta shells until just al dente according to the package directions. Drain and let cool slightly.
In a large bowl, combine the shredded chicken, Cajun seasoning, ricotta, mozzarella, Parmesan, cream cheese, heavy cream, and minced garlic. Mix until smooth and evenly combined.
Fill each cooked shell generously with the creamy chicken mixture.
Lightly grease a 9×13-inch baking dish and arrange the stuffed shells in a single layer.
Stir together the marinara sauce and chicken broth, then pour evenly over the shells.
Cover the baking dish with foil and bake for 30 minutes.
Remove the foil, drizzle with olive oil, and continue baking for another 15 minutes until the sauce is bubbling and the tops are lightly golden.
Garnish with fresh parsley before serving your Creamy Cajun Chicken Stuffed Shells.