Preheat your grill or grill pan over medium-high heat.
Season the chicken breast evenly with salt, black pepper, and garlic powder.
Grill the chicken breast for about 6-7 minutes per side, or until fully cooked and the internal temperature reaches 165°F. Once cooked, let it rest for a few minutes before slicing.
While the chicken is grilling, preheat your oven to 400°F. Toss the broccoli with olive oil, a pinch of salt, and a dash of black pepper in a bowl.
Spread the broccoli on a baking sheet and roast for 15-20 minutes, or until the edges are slightly crispy.
Prepare the quinoa according to package instructions if not already cooked; typically, bring water to a boil, add rinsed quinoa, reduce heat, cover, and simmer until water is absorbed.
Plate the sliced grilled chicken breast alongside the quinoa and roasted broccoli. Serve warm and enjoy your nutritious lunch.