Preheat your oven to 400°F (200°C) and line a large baking sheet with parchment paper.
In a small mixing bowl, whisk together the harissa paste, extra virgin olive oil, lemon juice, minced garlic, sea salt, and black pepper to create the marinade.
Slice the chicken breast into 1-inch strips and chop the red bell pepper into bite-sized pieces.
Place the chicken strips, broccoli florets, and bell pepper pieces onto the prepared baking sheet.
Pour the harissa marinade over the chicken and vegetables, using your hands or tongs to toss everything until evenly coated.
Spread the mixture out into a single layer to ensure the vegetables char properly and the chicken cooks evenly.
Roast in the oven for 18 to 22 minutes, or until the chicken reaches an internal temperature of 165°F and the broccoli edges are crispy.
Remove from the oven and let the chicken rest for 2 minutes before serving.