Preheat your oven to 400°F and line a large rimmed sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into uniform 1-inch bite-sized pieces and halve the baby potatoes so they cook evenly.
In a small glass bowl, whisk together the extra virgin olive oil, fresh lemon juice, dried oregano, garlic powder, sea salt, and black pepper.
Place the chicken pieces, halved potatoes, broccoli florets, and chopped red bell peppers onto the prepared sheet pan.
Drizzle the lemon-herb dressing over the chicken and vegetables, then use your hands or tongs to toss everything until thoroughly coated.
Spread the ingredients out into a single even layer, ensuring the pan is not overcrowded so the vegetables roast rather than steam.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the potatoes are fork-tender and golden.