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, and chop the broccoli and bell pepper into bite-sized florets and strips.
Toss the vegetables on the baking sheet with half of the olive oil, half of the sea salt, and half of the black pepper until evenly coated.
Roast the vegetables for 20 to 25 minutes, tossing halfway through, until the sweet potatoes are tender and the broccoli edges are slightly caramelized.
While vegetables roast, season the chicken breast on both sides with the garlic powder, dried oregano, and the remaining salt and pepper.
Heat the remaining olive oil in a stainless steel or cast-iron skillet over medium-high heat.
Place the chicken in the hot skillet and sear for 6 to 7 minutes per side, or until the exterior is golden brown and the internal temperature reaches 165°F.
Remove the chicken from the pan and let it rest for 5 minutes to lock in the juices before slicing and serving with the roasted vegetables.