Preheat oven to 400°F (200°C) and line a large sheet pan with parchment paper for easy cleanup.
Cut the chicken breast into 1-inch bite-sized cubes and place them in a large mixing bowl.
Chop broccoli into bite-sized florets and slice the red bell pepper into 1-inch strips, adding them to the bowl with the chicken.
In a small jar, whisk together the olive oil, lemon juice, lemon zest, minced garlic, oregano, salt, and pepper.
Pour the dressing over the chicken and vegetables, tossing thoroughly to ensure every piece is evenly coated.
Spread the mixture in a single layer on the prepared sheet pan, ensuring enough space for air to circulate and roast properly.
Roast for 18-22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.
Allow the meal to cool slightly before portioning into airtight containers for your weekly meal prep.