Preheat oven to 400°F (200°C). Line a baking sheet with parchment paper.
Whisk soy sauce, honey, pineapple juice, garlic, ginger, sesame oil, cornstarch, black pepper, and red pepper flakes in a bowl.
Toss chicken, pineapple, bell peppers, onion, and broccoli with olive oil and half the glaze in a large bowl.
Spread evenly on the baking sheet. Bake for 20-25 minutes, stirring halfway, until chicken reaches 165°F.
Drizzle with remaining glaze, toss, and garnish with green onions and sesame seeds.
Serve hot over rice or your favorite grain.