Preheat your oven to 425°F. Line a sheet pan with parchment paper for easy cleanup.
In a small bowl, whisk together lemon juice, olive oil, minced garlic, mixed dried herbs, salt, and pepper.
Place the chicken breast, cut into appropriate serving pieces if desired, on the sheet pan. Brush both sides with the lemon-herb marinade.
Dice the sweet potato into 1/2-inch cubes and cut broccoli into florets. Toss both vegetables with a little olive oil, salt, and pepper.
Arrange the sweet potatoes and broccoli around the chicken on the sheet pan, ensuring even distribution for uniform roasting.
Roast in the preheated oven for about 20-25 minutes until the chicken is cooked through (internal temperature 165°F) and the vegetables are tender and slightly caramelized.
If desired, broil the sheet pan for an additional 2-3 minutes to crisp up the edges. Serve immediately and enjoy.