Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Peel and cube the sweet potato into half-inch pieces, slice the carrots into rounds, and chop the red bell pepper into bite-sized chunks.
Place the broccoli, carrots, bell pepper, and sweet potato on the baking sheet. Drizzle with half of the avocado oil and season with a pinch of sea salt and black pepper.
Toss the vegetables to coat evenly and roast in the oven for 20 to 25 minutes, or until the sweet potatoes are tender and the broccoli edges are slightly charred.
While the vegetables roast, season the chicken breast on both sides with garlic powder, dried oregano, and the remaining sea salt and black pepper.
Heat the remaining avocado oil in a large skillet over medium-high heat. Once the pan is hot, add the chicken breast.
Sear the chicken for about 6 to 7 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F (74°C).
Remove the chicken from the pan and let it rest for 3 minutes before slicing.
Plate the sliced chicken alongside the roasted vegetable medley and finish with a fresh squeeze of lemon juice over the top.