Begin by preheating your grill or grill pan over medium-high heat.
In a small bowl, whisk together the lemon juice, olive oil (reserve a little extra for the broccoli if desired), fresh herbs, salt, and pepper.
Pat the chicken breast dry and lightly coat with half of the marinade. Allow it to sit for 10 minutes at room temperature while you prepare the quinoa and broccoli.
Rinse the quinoa under cold water, then cook according to package instructions, typically simmering in water until it is fluffy, about 15 minutes.
Meanwhile, cut the broccoli into florets. Toss with a drizzle of olive oil, salt, and pepper.
Place the broccoli on a baking sheet and roast in a preheated 425°F oven for about 15-20 minutes until tender and slightly crispy on the edges.
Grill the marinated chicken breast for approximately 6-7 minutes per side or until fully cooked and juicy.
Slice the chicken and plate alongside a serving of quinoa and roasted broccoli. Optionally, drizzle any remaining herb marinade over the top for extra flavor.
Serve warm and enjoy your balanced, nutrient-packed lunch.