Preheat your oven to 400°F (200°C). In a large bowl, toss the cubed chicken, pineapple chunks, bell peppers, and red onion with olive oil, salt, and pepper. Spread in an even layer on a large, rimmed baking sheet. Roast for 15-20 minutes, until the chicken is lightly browned and vegetables begin to soften.
While the chicken and veggies roast, prepare the sauce. In a small bowl, whisk together the soy sauce, honey, rice vinegar, minced garlic, grated ginger, and sesame oil. In a separate tiny bowl, whisk the cornstarch with 1 tablespoon of cold water to create a smooth slurry, then whisk this slurry into the main sauce mixture.
Carefully remove the hot sheet pan from the oven. Push the chicken and vegetable mixture to the sides of the pan to create a well in the center. Pour the rinsed rice into the center well. Pour the chicken broth directly over the rice.
Drizzle about two-thirds of the prepared sauce over the chicken and vegetables on the sides, tossing gently to coat. Tightly cover the entire sheet pan with aluminum foil to trap the steam. Return the pan to the oven and bake for another 20-25 minutes, until the liquid is absorbed and the rice is tender.
Remove the foil from the sheet pan. Drizzle the remaining sauce over everything and gently stir to combine the rice with the chicken and vegetables. For extra caramelization, you can switch the oven to broil for 1-2 minutes, watching carefully to prevent burning.
Let the dish rest for a few minutes. Garnish generously with sliced green onions and sesame seeds before serving hot directly from the pan.