Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Peel and cube the sweet potato into half-inch pieces, and slice the red bell pepper into thin strips.
In a large bowl, toss the sweet potato, broccoli florets, and bell pepper with half of the olive oil, half the sea salt, and half the black pepper.
Spread the vegetables in a single layer on the prepared baking sheet and roast for 20-25 minutes until tender and slightly caramelized.
While the vegetables roast, season the chicken breast evenly on both sides with the garlic powder, dried oregano, and the remaining salt and pepper.
Heat the remaining olive oil in a cast-iron or heavy skillet over medium-high heat.
Place the chicken in the skillet and sear for 6-7 minutes per side, or until golden brown and the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest for 3 minutes to lock in the juices.
Serve the pan-seared chicken alongside the roasted vegetable medley and finish with a fresh squeeze of lemon over everything.