Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
Place the broccoli florets, sliced red bell peppers, and zucchini on the baking sheet.
Drizzle the vegetables with half of the olive oil and sprinkle with half of the sea salt, black pepper, and all of the dried oregano.
Toss the vegetables well to coat and spread them in a single layer, then roast for 18 to 20 minutes until tender and slightly charred.
While the vegetables roast, season the chicken breast on both sides with garlic powder and the remaining sea salt and black pepper.
Heat the remaining olive oil in a heavy-bottomed skillet over medium-high heat.
Place the chicken in the hot skillet and sear for 6 to 7 minutes per side, or until the internal temperature reaches 165°F and the exterior is golden brown.
Remove the chicken from the pan and let it rest for 3 minutes before slicing.
Plate the sliced chicken alongside the roasted vegetables and finish the entire dish with a fresh squeeze of lemon juice.