Preheat your oven to 400°F (200 °C) and line a large baking sheet with parchment paper.
Toss the cubed sweet potatoes, broccoli florets, and sliced bell peppers with 0.5 tablespoons of olive oil, half the sea salt, and half the black pepper.
Spread the vegetables in a single layer on the baking sheet and roast for 20-25 minutes until the potatoes are tender and the broccoli edges are caramelized.
While the vegetables roast, season the chicken breast evenly on both sides with dried oregano, garlic powder, and the remaining sea salt and black pepper.
Heat the remaining 0.5 tablespoons of olive oil in a heavy-bottomed skillet over medium-high heat.
Place the chicken in the hot skillet and sear for 6 to 8 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Remove the chicken from the heat and let it rest for 3 minutes, then drizzle with fresh lemon juice before serving alongside the roasted vegetables.