Heat olive oil in a skillet over medium heat and sauté onion and bell pepper for 5 minutes until soft and fragrant.
Add minced garlic, then ground chicken, breaking it up and cooking until browned, about 6–8 minutes.
Stir in Cajun seasoning, smoked paprika, and cayenne for extra heat.
Pour in tomato sauce, ketchup, Worcestershire sauce, and brown sugar, stirring to combine.
Simmer uncovered for 5–7 minutes until the sauce thickens, adding a little water if needed.
Spoon the mixture onto toasted buns, top with chopped parsley, and serve hot.