In a bowl, combine 1/2 tablespoon of olive oil, garlic powder, lemon juice, salt, and pepper to create a marinade for the chicken.
Coat the chicken breast with the marinade and set aside for at least 15 minutes to absorb the flavors.
Preheat the grill to medium-high heat while you prepare the side dishes.
Place the marinated chicken on the grill and cook for about 5-6 minutes per side until the internal temperature reaches 165°F.
Meanwhile, preheat your oven to 425°F for roasting the broccoli.
Toss the broccoli florets with 1 tablespoon of olive oil, salt, and pepper on a baking sheet.
Roast the broccoli in the oven for about 15-20 minutes until tender and slightly crispy on the edges.
Prepare the quinoa according to package instructions if not already cooked; generally, simmer for about 15 minutes until fluffy.
Plate the dish by placing a serving of quinoa, adding the roasted broccoli, and slicing the grilled chicken breast on top.
Serve immediately and enjoy your balanced, nutrient-packed lunch.