Preheat oven to 425 F. Line a baking sheet with parchment paper.
In a large shallow bowl, combine and mix; 2 tablespoons olive oil, 1 teaspoon cumin, 1-1/2 teaspoon sumac, 1/2 teaspoon cinnamon, 1/2 teaspoon allspice, 1 teaspoon kosher salt, and a few grinds of freshly ground black pepper. Add the chicken breasts and coat them with the spice mixture.
Transfer the chicken breasts to the baking sheet. Roast the chicken for about 30 minutes or until instant-read-thermometer registers 160 F. Remove from oven, cover with foil, and set a side.
Meanwhile, in a large sauté pan over medium heat, add 2 tablespoons of olive oil. Add the pine nuts and cook, stirring until they are golden about 3-4 minutes. Transfer the pine nuts to a plate lined with paper towels, reserve the oil in the pan. Add the remaining 1/4 cup olive oil to the sauté pan. Add the sliced red onions and 3/4 teaspoon kosher salt. Continue to cook over medium heat for about 15 minutes, stirring occasionally until the onions are soft and pale golden but not caramelized. Add the 2 tablespoons of sumac, remaining 2 teaspoons of cumin, and some freshly ground black pepper. Stir to mix and then remove from the heat and set aside.
Just before serving; preheat the broiler and tear the naan bread into fourths. Put the naan pieces on a baking sheet and place under the broiler for about 2-3 minutes, just to crisp the bread slightly.
To serve: Arrange the naan bread on a platter. Top the bread with half of the onions, followed by the chicken and any juices left in the pan. (I like to tear the chicken breasts into 3 to 4 pieces before placing them on the bread). Top the chicken with the remaining onions, followed by the pine nuts, parsley, a sprinkling of sumac and a drizzle of extra virgin olive oil. Serve with plain Greek yogurt and lemon wedges.