Preheat the grill or grill pan to medium-high heat.
Season the chicken breast with salt, pepper, and a pinch of garlic powder on both sides.
Lightly brush the chicken with a small amount of olive oil to help prevent sticking.
Grill the chicken breast for about 6-7 minutes per side or until it reaches an internal temperature of 165°F.
While the chicken is grilling, preheat your oven to 425°F for the broccoli.
Toss the broccoli florets with the remaining olive oil, salt, and pepper, and spread evenly 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 as per package instructions if not already cooked, ensuring a light and fluffy texture.
To serve, place the cooked quinoa on a plate, top with sliced grilled chicken breast, and add a serving of roasted broccoli.
Finish with an optional squeeze of lemon juice over the chicken for extra brightness.