Prep your station. Preheat the grill to medium-high heat (about 400°F), or heat your oven to 400°F. Tear four large sheets of heavy-duty foil, each about 12–14 inches long.
Cut the chicken. Slice chicken into 1-inch pieces or thin strips so it cooks evenly and quickly in the packets. Pat dry with paper towels.
Season generously. In a bowl, toss chicken with olive oil, garlic, salt, pepper, and smoked paprika.
Add a spoonful of BBQ sauce and mix so every piece is lightly coated.
Arrange the base. On each foil sheet, pile a handful of bell peppers, red onion, and pineapple chunks in the center. Drizzle with a little olive oil and a pinch of salt.
Add chicken and sauce. Top the veggies with seasoned chicken. Spoon 2–3 tablespoons of BBQ sauce over each packet.
If you like heat, sprinkle a pinch of chili flakes.
Seal it right. Bring the long sides of the foil up and together, fold down tightly, then fold in the ends to seal. Leave a small bit of headspace so steam can circulate inside.
Cook. Grill: Place packets seam-side up, cover, and cook 18–22 minutes, flipping once halfway.
Oven: Place packets on a baking sheet and roast 22–25 minutes.
Campfire: Set on a grate over medium coals, 18–22 minutes, turning once.
Check for doneness. Carefully open one packet (watch for hot steam). Chicken should be 165°F in the center and opaque throughout.
Veggies should be tender-crisp.
Finish with flair. Drizzle a little extra BBQ sauce if you want it saucier. Squeeze lime over the top and sprinkle with chopped cilantro or parsley.
Serve. Eat straight from the packet or spoon over rice or quinoa. Add a side salad or grilled corn for a full meal.