Preheat the oven to 400°F and line a 9x13” baking sheet with parchment paper for easy cleanup.
In a small bowl, combine the BBQ sauce, teriyaki sauce, and soy sauce.
Cut the bell peppers and onion into 1” bite-sized pieces and transfer them to the baking sheet along with the broccoli. Pour half of the sauce onto the vegetables and toss to coat. Spread in an even layer.
Season both sides of the chicken thighs with salt, pepper, and garlic powder. Make room and place the chicken thighs on the baking sheet.
Using ¼ cup of the remaining sauce, coat the chicken, then flip and coat the other side. Save the remaining sauce for later.
Place in the oven and cook for 25 minutes. Remove from the oven and add fresh pineapple chunks around the chicken. Return to the oven and continue baking for 5 to 10 more minutes, or until the chicken is cooked through (internal temperature should reach 165°F).
Turn the oven to broil and bake for 1 to 2 minutes until the chicken is browned. Keep an eye on them as they can burn quickly!
Remove from the oven and spread the remaining sauce on the chicken.
Garnish with chopped cilantro and sesame seeds. Serve with rice, if desired. Enjoy!