Preheat your grill to medium-high heat or prepare a grill pan over medium heat.
Season the chicken breast on both sides with salt, black pepper, and garlic powder.
Grill the chicken breast for about 6-7 minutes per side or until the internal temperature reaches 165°F. Remove from heat and let it rest for a few minutes before slicing.
While the chicken is grilling, preheat your oven to 425°F for the broccoli.
Toss the broccoli florets with a teaspoon of olive oil, a pinch of salt, and black pepper. Spread evenly on a baking sheet.
Roast the broccoli in the oven for 15-20 minutes, stirring halfway through, until edges are slightly crispy.
Prepare the quinoa according to package instructions if not already cooked. Use about 0.75 cup of cooked quinoa for the serving.
Assemble the dish by plating the quinoa, topping it with sliced grilled chicken, and adding the roasted broccoli on the side.
Serve warm and enjoy your nutritious, balanced lunch.