Preheat your oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Dice the chicken breast into 1-inch bite-sized pieces and cube the sweet potato into small 1/2-inch chunks to ensure even cooking.
Chop the broccoli into small florets and slice the red bell pepper into 1-inch strips.
Place the chicken, sweet potato, broccoli, and bell pepper onto the prepared sheet pan.
Drizzle the olive oil and lemon juice over the chicken and vegetables, then sprinkle evenly with dried oregano, garlic powder, sea salt, and black pepper.
Toss everything together directly on the pan until thoroughly coated, then spread into a single layer.
Roast in the oven for 20-25 minutes, or until the chicken is cooked through and the sweet potatoes are tender when pierced with a fork.
Remove from the oven and let cool slightly before dividing into meal prep containers for the week.