Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Dice the sweet potato into small half-inch cubes and mince the garlic cloves finely.
In a large bowl, whisk together the avocado oil, minced garlic, rosemary, thyme, sea salt, and black pepper.
Add the chicken breast, sweet potato cubes, and broccoli florets to the bowl, tossing thoroughly until everything is evenly coated in the herb oil.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the chicken and vegetables are not overcrowded.
Roast for 20-25 minutes, or until the chicken reaches an internal temperature of 165°F and the sweet potatoes are fork-tender.
Remove from the oven and drizzle with fresh lemon juice before serving to brighten the flavors.