Place brown rice and water in a medium sauce pan over medium heat. Bring to a boil. Cover, reduce heat to low and let simmer for 30 minutes. Turn off heat and let sit for 15 minutes before fluffing with a fork.
Preheat oven to 400 degrees F. Place butternut squash cubes, sliced onion and broccoli florets on a large baking sheet. Sprinkle with chili powder. Cook for 25 minutes or until squash is soft.
Heat corn in a small saucepan on the stove over medium heat or by microwaving for 90 seconds.
Begin assembling by dividing rice into 4 bowls. Top with 1/4 of roasted vegetables, cooked corn, black beans and sliced bell peppers.