Preheat and Prepare: Preheat your oven to 425°F (220°C). Line two large, rimmed baking sheets with parchment paper. This prevents sticking and ensures even browning.
Make the Rub: In a medium bowl, combine all the Aromatic Herb Rub ingredients: minced garlic, rosemary, oregano, onion powder, coriander, smoked paprika, black pepper, and sea salt. Stir until you have a thick, fragrant paste.
Marinate the Chicken: Add the chicken breasts to the bowl with the rub. Using your hands, massage the paste thoroughly into the chicken, ensuring it's fully coated. Set aside while you prepare the vegetables.
Dress the Vegetables: In a large mixing bowl, combine the drained chickpeas, artichoke hearts, Kalamata olives, red onion, bell peppers, and cherry tomatoes. In a separate small bowl, whisk together the extra virgin olive oil, lemon juice, lemon zest, and sumac. Pour this dressing over the vegetables and toss gently until everything is evenly coated.
Assemble the Pans: Divide the vegetable mixture evenly between the two prepared baking sheets, spreading them into a single layer. Arrange the marinated chicken breasts among the vegetables, ensuring nothing is too crowded.
Roast to Perfection: Place the pans in the oven and roast for 20-25 minutes, rotating the pans halfway through. The chicken is done when it is cooked through (reaching an internal temperature of 165°F or 74°C) and the vegetables are tender and lightly caramelized at the edges.
Rest and Serve: Remove the sheet pans from the oven. Let the chicken rest on the pan for 5 minutes before slicing. Garnish everything generously with fresh parsley. Serve immediately with farro or quinoa and a fresh lemon wedge on the side.