Combine 2 tablespoons harissa, 1 tablespoon olive oil, cumin, coriander, caraway, paprika, salt, and pepper. Toss thoroughly with the chicken thighs. Cook immediately or refrigerate for 30 minutes to 4 hours for deeper flavor.

Heat a large Dutch oven or deep skillet over medium-high heat. Add the chicken in a single layer and sear without moving for about 4 minutes. Flip and cook another 2-3 minutes. The goal is deep browning rather than cooking the thighs through. Transfer to a plate.

Reduce heat to medium and add another tablespoon of olive oil if the pan looks dry. Add the onion and cook for 5-7 minutes, scraping up the browned chicken bits. Add garlic, 1 tablespoon harissa, cumin, coriander, and caraway and cook about 60 seconds. Add tomato paste and cook another 1-2 minutes, until slightly darkened.

Add tomatoes, chickpeas, chicken stock, and 1/2 teaspoon salt. Stir well and bring to a simmer. Return the chicken and accumulated juices to the pan, nestling the thighs partially into the chickpeas. Reduce to medium-low and simmer uncovered for 20-25 minutes, turning the chicken once, until tender and the sauce has reduced. If the sauce gets too thick before the chicken is ready, add a splash of stock or water.

Remove from the heat. Add the zest of 1/2 lemon, 1-2 tablespoons fresh lemon juice, most of the chopped herbs, and a drizzle of extra-virgin olive oil. Taste and adjust with additional lemon, salt, or harissa as needed. Scatter the remaining herbs over the top.