Preheat your oven to 400°F and line a large, rimmed baking sheet with unbleached parchment paper to prevent sticking without using extra fats.
Dice the sweet potato and carrots into uniform 1/2-inch cubes and halve the Brussels sprouts to ensure everything cooks at the same rate.
Slice the organic, air-chilled chicken breast into 1-inch chunks, which allows them to stay juicy while developing a nice exterior crust.
In a large mixing bowl, combine the avocado oil with dried rosemary, thyme, garlic powder, sea salt, and black pepper.
Add the chicken and chopped vegetables to the bowl, using your hands or a spatula to coat every piece with the fragrant herb oil.
Spread the mixture across the prepared baking sheet in a single layer, making sure there is plenty of space between pieces so they roast rather than steam.
Roast for 25 to 30 minutes, giving the pan a good shake halfway through, until the chicken is cooked through and the vegetables are tender with caramelized edges.