Preheat your oven to 400°F (200°C) and heat a grill pan or outdoor grill to medium-high heat.
Place the broccoli florets on a baking sheet, toss with half of the olive oil, salt, and pepper, then roast for 15-20 minutes until the edges are tender and slightly charred.
While the broccoli roasts, prepare the quinoa by simmering in water or low-sodium broth until all liquid is absorbed and the grains are fluffy.
Season the chicken breast with garlic powder, salt, pepper, and the remaining olive oil.
Grill the chicken for 6-7 minutes per side, or until the internal temperature reaches 165°F (74°C).
Let the chicken rest for 3 minutes before slicing into strips.
Assemble the bowl by placing the cooked quinoa at the base, topping it with the grilled chicken and roasted broccoli.
Drizzle the entire dish with fresh lemon juice just before serving.