Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Slice the chicken breast into 1-inch bite-sized cubes and halve the baby potatoes.
Cut the broccoli into small florets and dice the red bell pepper into 1-inch squares.
In a small mixing bowl, whisk together the extra virgin olive oil, fresh lemon juice, minced garlic cloves, dried oregano, sea salt, and black pepper.
Place the chicken, potatoes, broccoli, and bell peppers onto the prepared sheet pan.
Drizzle the lemon-herb dressing over the chicken and vegetables, then toss thoroughly with tongs to ensure every piece is well-coated.
Spread the ingredients out into a single even layer, ensuring they are not overcrowded so they roast rather than steam.
Bake in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the potatoes are fork-tender.
Remove from the oven and serve immediately while hot and fragrant.