Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Peel and dice the sweet potato into 1/2-inch cubes, and chop the broccoli and bell pepper into bite-sized pieces.
Slice the chicken breast into even 1-inch strips to ensure they cook at the same rate as the vegetables.
In a large mixing bowl, whisk together the olive oil, lemon juice, lemon zest, oregano, garlic powder, sea salt, and black pepper.
Add the chicken strips and all the chopped vegetables to the bowl, tossing until every piece is thoroughly coated in the herb marinade.
Spread the mixture in a single layer on the prepared baking sheet, making sure not to crowd the pan so the vegetables can roast rather than steam.
Bake for 20 to 25 minutes, or until the chicken is cooked through and the sweet potatoes are tender and lightly caramelized.
Allow the meal to cool slightly before portioning into airtight containers for a high-protein, meal-prep friendly lunch.