Preheat your oven to 400°F and line a large rimmed baking sheet with parchment paper for easy cleanup.
Pat the chicken breast dry with a paper towel and cut it into uniform one-inch cubes.
Trim the broccoli into bite-sized florets, ensuring they are roughly the same size as the chicken for even cooking.
In a large mixing bowl, whisk together the extra virgin olive oil, minced garlic, lemon juice, lemon zest, sea salt, and black pepper.
Add the chicken cubes and broccoli florets to the bowl, tossing thoroughly until every piece is well-coated in the garlic-lemon mixture.
Spread the ingredients in a single layer on the prepared baking sheet, making sure not to overcrowd the pan so the broccoli can crisp up.
Roast for 18 to 22 minutes, tossing halfway through, until the chicken is cooked through and the broccoli edges are beautifully charred.
Serve the roasted mixture over a bed of warm quinoa to soak up any remaining citrus juices.