Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Dice the sweet potato, zucchini, and carrots into uniform half-inch cubes for even cooking.
Toss the vegetables on the baking sheet with half of the olive oil, sea salt, and black pepper.
Roast the vegetables for 20 to 25 minutes until they are tender and slightly caramelized on the edges.
While the vegetables roast, season the chicken breast with garlic powder, dried oregano, and the remaining salt and pepper.
Heat the remaining olive oil in a skillet over medium-high heat and sear the chicken for 6 to 7 minutes per side until fully cooked.
Allow the chicken to rest for a few minutes before slicing it into thin strips.
Assemble the bowl by layering the warm brown rice at the bottom and topping it with the roasted vegetables and sliced chicken.