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 cubes and chop the broccoli and bell pepper into uniform, bite-sized pieces.
In a large mixing bowl, whisk together the olive oil, minced garlic, dried thyme, dried rosemary, sea salt, and black pepper.
Add the chicken and vegetables to the bowl, tossing thoroughly until every piece is evenly coated in the herb oil.
Spread the mixture in a single layer across the prepared sheet pan, ensuring enough space between pieces for roasting rather than steaming.
Roast for 18-22 minutes, or until the chicken is cooked through and the vegetables are tender with slightly charred, golden edges.
Squeeze the fresh lemon juice over the entire pan immediately after removing from the oven to brighten the flavors.
Divide the mixture into meal prep containers and store in the refrigerator for up to 4 days.