Preheat your oven to 400°F (200°C).
Chop the broccoli, red bell pepper, and zucchini into uniform, bite-sized pieces.
On a large baking sheet, toss the vegetables with 1 tablespoon of olive oil and half of the sea salt, black pepper, and dried oregano.
Spread the vegetables in a single layer and roast for 20 minutes until tender and slightly caramelized at the edges.
While the vegetables roast, season the chicken breast on both sides with the remaining sea salt, black pepper, garlic powder, and oregano.
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 internal temperature reaches 165°F.
Remove the chicken from the heat and drizzle with fresh lemon juice.
Serve the pan-seared chicken alongside the warm roasted vegetables.