Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper.
Dice the chicken breast and sweet potato into small, toddler-friendly 1/2-inch cubes to ensure even cooking.
Chop the broccoli into bite-sized florets and slice the red bell pepper into thin strips.
In a small bowl, whisk together the olive oil, lemon juice, oregano, garlic powder, salt, and pepper.
Place the chicken and all the vegetables on the prepared sheet pan.
Drizzle the lemon-herb mixture over the ingredients and toss thoroughly until everything is well-coated.
Spread the mixture in a single layer, ensuring nothing is overcrowded so the veggies roast rather than steam.
Bake for 20-25 minutes, or until the chicken is cooked through and the sweet potatoes are fork-tender.