Preheat your oven to 400°F (200°C) and line a large rimmed baking sheet with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch cubes and chop the broccoli, bell pepper, and zucchini into uniform, bite-sized pieces.
In a small bowl, whisk together the extra virgin olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Place the chicken and vegetables in a large mixing bowl, pour the marinade over them, and toss thoroughly to ensure every piece is well-coated.
Spread the mixture in a single, even layer on the prepared baking sheet, making sure not to overcrowd the pan so the vegetables roast rather than steam.
Roast in the center of the oven for 20-25 minutes, tossing halfway through, until the chicken is cooked through and the vegetables have developed golden, charred edges.
Remove from the oven and let rest for 2 minutes before serving warm with an optional extra squeeze of fresh lemon.