Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper.
Rinse the white rice under cold water until clear, then combine with 0.5 cup water in a small saucepan; bring to a boil, then simmer covered for 15 minutes or until tender.
While the rice cooks, dice the chicken breast, sweet potato, carrots, and zucchini into uniform 1-inch pieces to ensure they roast evenly.
Place the chicken and chopped vegetables onto the prepared baking sheet.
Drizzle with olive oil and sprinkle with sea salt, black pepper, and garlic powder, tossing well to ensure every piece is coated.
Spread the mixture into a single layer and roast for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the sweet potatoes are caramelized.
Fluff the cooked rice with a fork and divide it into bowls, topping with the roasted chicken and vegetable medley.