Prepare the ingredients. Rinse the rice under cool water. Cut the chicken into even strips or bite size chunks. Chop the broccoli, carrots, and bell pepper into similar sized pieces so they cook evenly. Heat the oven to 220 degrees Celsius, which is about 425 degrees Fahrenheit.
Cook the rice. Place the rinsed rice and water in a medium saucepan with the salt. Bring to a gentle boil over medium heat, then reduce the heat to low. Cover the pot and simmer until the rice is tender and the water is absorbed. This usually takes about 20 to 25 minutes for brown rice and a little less for white rice. Turn off the heat and let the rice rest with the lid on for 5 minutes, then fluff with a fork.
Season the chicken. In a large mixing bowl combine the chicken pieces with olive oil, salt, black pepper, garlic powder, and paprika. Toss well so all sides are coated with oil and spices. Arrange the seasoned chicken in a single layer on one side of the large baking sheet.
Prepare the vegetables. In the same bowl that held the chicken or in a clean bowl, toss the broccoli florets, carrot slices, and bell pepper strips with the olive oil, salt, and black pepper. Spread the vegetables in a single layer on the empty side of the baking sheet. If your tray is small, use a second tray so the pieces are not crowded.
Bake the chicken and vegetables. Place the baking sheet in the hot oven. Bake for about 20 to 25 minutes, stirring the vegetables once halfway through. The chicken is done when the thickest pieces are no longer pink in the center and the juices run clear. The vegetables should be tender with light browning at the edges. If your oven runs hot, check a little earlier so nothing dries out.
Make the yogurt sauce. While the chicken and vegetables bake, prepare the sauce. In a small bowl stir together the Greek yogurt, lemon juice, minced garlic or garlic powder, salt, and black pepper until smooth. Taste and adjust seasoning if needed. If you prefer a thinner sauce, stir in a spoon or two of water until it reaches a drizzle texture.
Cool the components slightly. When the chicken and vegetables are done, remove the tray from the oven and let everything cool for about 10 minutes. This short rest helps the juices settle in the chicken and makes it easier to handle the food when portioning into containers.
Build the meal prep bowls. Place your four meal prep containers on the counter. Add an equal amount of rice to each container, roughly one heaped half cup. Top the rice with a generous portion of chicken in each container, using all of the chicken between the four bowls. Divide the roasted vegetables between the containers, filling any remaining space.
Add the sauce and toppings. Spoon the yogurt sauce into four small containers so you can add it fresh when you eat, or place a spoon of sauce directly on each bowl if you prefer. Sprinkle chopped parsley or cilantro over the top of the bowls. Add a few nuts or seeds if you like extra crunch.
Store the meals. Let the prepared bowls cool to room temperature, then seal tightly with lids. Place in the refrigerator within two hours of cooking. For the best quality, enjoy these high protein meal prep bowls within three to four days. If you want to keep some for later, freeze one or two bowls and thaw them in the refrigerator the day before you plan to eat them.
Reheat and serve. When ready to eat, remove the lid and take out the sauce container if it is packed separately. Reheat the bowl in the microwave until hot all the way through, usually one to three minutes depending on your microwave. Stir in or drizzle the yogurt sauce just before eating. Add a squeeze of fresh lemon if you like extra brightness.