Preheat your oven to 400°F (200°C).

Line a large sheet pan with parchment paper or foil for easy cleanup. Lightly grease with cooking spray if desired.

In a bowl, whisk together the soy sauce, olive oil, garlic powder, paprika, salt, and pepper. Stir in honey, ginger, or red pepper flakes if using.

Place the chicken cubes in a bowl or zip-top bag and pour in half of the marinade. Toss to coat evenly. Let sit for 15–30 minutes at room temperature (or up to 4 hours in the fridge). Bring to room temperature before roasting.

Cut the bell pepper, red onion, and pineapple into similar-sized chunks (about 1 inch) to ensure even cooking. Drain pineapple thoroughly if using canned.

Spread the marinated chicken evenly across the baking sheet. Add the chopped vegetables and pineapple, spacing them out so nothing is crowded. Use two pans if needed.

Pour the remaining marinade over the vegetables and pineapple. Toss everything gently to coat, then spread it out in a single, even layer.

Roast for 15 minutes. Stir or flip the ingredients, then roast for another 10–15 minutes, or until the chicken is fully cooked (165°F internal temp) and the veggies are tender and slightly caramelized.

Remove from the oven and let rest for 5 minutes before serving. This helps the juices settle for moist, flavorful bites.

Serve hot over cooked rice or quinoa, or enjoy it as a low-carb dish. Garnish with chopped parsley or cilantro, sliced green onions, and lime wedges if desired.