Preheat your oven to 400°F (200°C) and line a large rimmed sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized pieces and halve the baby potatoes so they cook evenly.
Chop the broccoli into small florets, slice the zucchini into half-moons, and dice the red bell pepper into 1-inch squares.
In a small mixing bowl, whisk together the extra virgin olive oil, lemon juice, minced garlic, dried oregano, sea salt, and black pepper.
Place the chicken pieces, potatoes, broccoli, zucchini, and bell peppers onto the prepared sheet pan.
Drizzle the lemon-herb marinade over the ingredients and toss thoroughly with your hands or tongs until every piece is well-coated.
Spread the mixture out into a single layer, ensuring the chicken and vegetables are not overcrowded.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the potatoes are golden and fork-tender.
Remove from the oven and let rest for 2 minutes before serving warm.