Preheat your oven to 400°F and line a large baking sheet with parchment paper for easy cleanup.
Cut the chicken breast and sweet potato into 1-inch cubes, chop the bell pepper into bite-sized pieces, and slice the zucchini into half-moons.
In a small mixing bowl, whisk together the olive oil, lemon juice, dried oregano, garlic powder, sea salt, and black pepper to create the marinade.
Arrange the chicken cubes and all the prepared vegetables on the sheet pan in a single layer to ensure even roasting.
Drizzle the lemon-herb dressing over the chicken and vegetables, tossing thoroughly with your hands or tongs until everything is well-coated.
Roast in the center of the oven for 20 to 25 minutes, or until the chicken is cooked through and the sweet potatoes are fork-tender.
Remove from the oven and let the meal cool slightly before transferring it into an airtight meal prep container for the week.