Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Dice the sweet potato, zucchini, and red bell pepper into bite-sized pieces, and break the broccoli into small florets.
On the baking sheet, toss the chopped vegetables with 0.5 tablespoon of olive oil, half of the sea salt, half of the black pepper, and half of the dried oregano.
Spread the vegetables in a single layer and roast for 20 to 25 minutes until the sweet potatoes are tender and the edges are slightly caramelized.
While the vegetables roast, season the chicken breast on both sides with the remaining sea salt, black pepper, dried oregano, and the garlic powder.
Heat the remaining 0.5 tablespoon of olive oil in a heavy skillet over medium-high heat.
Place the chicken in the 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 before slicing it and serving alongside the roasted vegetable medley.