Preheat your oven to 400°F and line a large sheet pan with parchment paper.
Cut the chicken breast into 1-inch cubes and chop the broccoli and red bell pepper into bite-sized pieces.
Place the chicken and vegetables onto the prepared baking sheet, drizzle with olive oil, and sprinkle with sea salt, black pepper, and garlic powder.
Toss everything thoroughly to ensure an even coating of oil and spices, then spread into a single layer.
Roast in the oven for 18 to 20 minutes, or until the chicken is cooked through and the vegetables are slightly charred.
Add the cooked quinoa to your meal prep container and top with the roasted chicken and vegetable mixture.
In a small bowl, whisk together the lemon juice and chopped parsley, then drizzle the dressing over the bowl before serving or storing.