In a medium bowl, whisk together the ketchup, honey, vinegar, Worcestershire sauce, garlic, paprika, salt, chili powder, and black pepper.
Place the chicken pieces in a gallon-size resealable bag or shallow dish. Pour the marinade over the chicken and toss to coat evenly.
Seal the bag or cover the dish and refrigerate for 2 to 24 hours for maximum flavor.
Preheat a pellet grill or regular grill to medium to medium-high heat.
Cut the pineapple, bell peppers, and red onion into 1 to 1½-inch pieces.
Thread the chicken, pineapple, peppers, and onions onto skewers. Repeat the pattern until the skewers are filled.
Grill the BBQ Chicken Pineapple Skewers, turning once halfway through cooking. Grill chicken breasts for about 4 to 5 minutes per side or chicken thighs for about 6 to 7 minutes per side, until fully cooked.
Remove from the grill and serve immediately.