Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper for easy cleanup.
Slice the red bell pepper into thin strips and break the broccoli into bite-sized florets.
Place the chicken breast, broccoli florets, and bell pepper strips onto the prepared baking sheet in a single layer.
Drizzle the olive oil over the chicken and the vegetables, ensuring everything is lightly coated.
Sprinkle the dried rosemary, dried thyme, sea salt, black pepper, and garlic powder evenly over the entire tray.
Use your hands or tongs to toss the vegetables and rub the spices into the chicken so every bite is seasoned.
Roast in the oven for 20 to 25 minutes, or until the chicken reaches an internal temperature of 165°F and the vegetables are slightly charred.
Remove from the oven and immediately drizzle with fresh lemon juice to brighten the flavors before serving.