Season the chicken breast with sea salt, black pepper, and garlic powder.
Heat half of the olive oil in a grill pan over medium-high heat and cook the chicken for 6-7 minutes per side until the internal temperature reaches 165°F.
While the chicken cooks, dice the bell pepper, zucchini, and red onion into bite-sized pieces.
Sauté the vegetables in a separate skillet with the remaining olive oil until they are tender and show slight char marks.
Warm the pre-cooked brown rice and black beans together in a small saucepan or microwave until heated through.
Slice the grilled chicken into thin strips or cubes.
Assemble the bowl by placing the rice and bean mixture at the base, then topping with the sautéed vegetables and grilled chicken.
Finish the dish by adding fresh diced mango and sliced avocado on top for a creamy, sweet contrast.
Garnish with a squeeze of fresh lime juice and chopped cilantro if desired.