Preheat your oven to 400°F and line a large baking sheet with parchment paper.
Slice the chicken breast into 1-inch strips and chop the bell peppers, red onion, and zucchini into bite-sized pieces.
In a large mixing bowl, whisk together the harissa paste, olive oil, sea salt, and black pepper.
Add the chicken and vegetables to the bowl, tossing thoroughly until everything is coated in the vibrant red harissa marinade.
Spread the mixture in a single layer on the prepared baking sheet, ensuring the chicken pieces are not crowded.
Roast for 18 to 22 minutes, or until the chicken is cooked through and the vegetables are tender and slightly charred.
Remove from the oven, drizzle with fresh lemon juice, and garnish with chopped parsley before serving.