Preheat oven to 400 degrees Fahrenheit (200 degrees Celsius).
Prepare the marinade by whisking together olive oil, minced garlic, lemon juice, lemon zest, dried oregano, salt, and pepper in a small mixing bowl.
Arrange the cubed chicken and broccoli florets in a single layer on a large rimmed baking sheet.
Pour the marinade over the chicken and broccoli, tossing thoroughly to ensure even coating.
Roast for 20 to 25 minutes or until the internal temperature of the chicken reaches 165 degrees Fahrenheit (74 degrees Celsius).
Divide the 2 cups of cooked brown rice equally into four airtight meal prep containers.
Distribute the roasted chicken and broccoli evenly over the rice portions.
Garnish with fresh parsley and allow to cool slightly before sealing and refrigerating for up to 4 days.