Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper or drizzle lightly with olive oil.

In a large mixing bowl, combine the pineapple, red bell pepper, yellow bell pepper, and red onion. Drizzle with olive oil, sprinkle with garlic powder, salt, and pepper, and toss until coated.

Spread the chicken breasts evenly on the baking sheet and distribute the vegetable mixture around the chicken.

In a small bowl, whisk together the teriyaki sauce, soy sauce, honey, and rice vinegar. Pour the sauce over the chicken and vegetables.

Roast in the oven for about 25-30 minutes until the chicken reaches 165°F (74°C) and the vegetables are tender.

Let it rest for a few minutes, then garnish with sesame seeds and green onions.

Serve the teriyaki chicken and pineapple over a bed of cooked rice, if desired.