Preheat oven to 425°F. Line a large sheet pan with foil and lightly oil it.
Whisk soy sauce, pineapple juice, brown sugar, rice vinegar, ketchup, garlic, ginger, and sesame oil in a bowl.
Reserve about half of the sauce in a small bowl for basting. Set it aside.
Pat chicken dry. Toss chicken with the remaining sauce and let sit 10 minutes while you prep veggies.
Combine bell pepper, red onion, and pineapple on the sheet pan. Drizzle with olive oil, salt, and pepper; toss to coat.
Nestle marinated chicken among the veggies, shaking off excess marinade. Discard any marinade left in that bowl.
Bake 18 minutes. Brush chicken with the reserved sauce, then bake 6–8 minutes more until chicken reaches 165°F.
Broil 2 minutes to lightly caramelize, watching closely. Rest 5 minutes on the pan.
Scatter green onions and sesame seeds over the top. Serve with the pan juices spooned over.
Notes
Variation: Add heat with 1 tsp chili-garlic sauce in the glaze. Swap thighs for 1.25 lb chicken breast strips and reduce bake time by 3–4 minutes. Serve over coconut rice or with a crisp green salad.Storage: Refrigerate leftovers in an airtight container up to 3 days. Reheat on a sheet pan at 375°F for 8–10 minutes.This recipe is an original creation inspired by classic Easy Hawaiian Chicken Sheet Pan Recipe flavors. All ingredient ratios and instructions are independently developed.