Preheat the oven to 400°F.
In a small bowl, combine lemon juice, olive oil, mixed dried herbs, garlic powder, salt, and pepper to form the marinade.
Pat the chicken breast dry and rub the marinade all over it. Let it rest for 10 minutes to absorb the flavors.
Cut the broccoli into florets and slice the sweet potato into rounds or cubes.
Toss the broccoli and sweet potato with a pinch of salt, pepper, and a drizzle of olive oil.
Place the chicken breast on a baking sheet lined with parchment paper. Arrange the broccoli and sweet potato around the chicken.
Roast everything in the preheated oven for 20-25 minutes, or until the chicken is cooked through (internal temperature 165°F) and the vegetables are tender and slightly crispy.
Plate the chicken alongside the roasted broccoli and sweet potato, and enjoy this balanced, flavorful meal.