Mix Spices: Combine paprika, garlic powder, onion powder, oregano, thyme, and cayenne pepper in a small bowl. Set aside.
Cook Chicken: Heat olive oil in a large skillet over medium-high heat. Add ground chicken and cook, breaking apart with a wooden spoon, for 5-6 minutes until no longer pink.
Add Vegetables: Add diced onion and bell pepper. Cook for 3-4 minutes until softened. Add garlic and cook 1 minute more.
Season: Sprinkle Cajun seasoning over mixture and stir in tomato paste. Cook for 1 minute.
Create Sauce: Add tomato sauce, Worcestershire sauce, and brown sugar. Season with salt and pepper. Reduce heat to medium-low and simmer 8-10 minutes until thickened.
Toast Buns: Butter buns and toast until golden brown in a separate pan or under broiler.
Serve: Spoon chicken mixture onto bottom buns. Add desired toppings and crown with top bun.