Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Slice the chicken breast into even 1-inch strips and halve the baby potatoes to ensure everything cooks at the same rate.
In a small bowl, whisk together the olive oil, lemon juice, lemon zest, dried rosemary, garlic powder, sea salt, and black pepper.
Place the chicken strips, halved potatoes, broccoli florets, and sliced bell peppers onto the prepared sheet pan.
Drizzle the lemon-herb oil mixture over the ingredients and toss thoroughly with your hands or tongs to coat every piece evenly.
Spread the ingredients into a single layer, ensuring the chicken and vegetables 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 the vegetables are crisp and the chicken is juicy.