Start by seasoning the chicken thighs generously with kosher salt and freshly ground black pepper on both sides.
In a large skillet, heat the olive oil over medium-high heat. Add the chicken thighs, skin-side down, and sear for about 6-7 minutes until golden brown. Flip and cook for another 5-6 minutes. Remove chicken and set aside.
Add the finely chopped onion to the same skillet and sauté for about 3-4 minutes until softened. Then, add the minced garlic and cook for another minute until fragrant.
Stir in the tomato paste and cook for an additional 2 minutes. Add the drained chickpeas and stir to combine.
Pour in the harissa and chicken stock, stirring to coat the chickpeas.
Return the seared chicken thighs to the skillet, skin-side up. Cover and simmer on medium-low heat for about 20-25 minutes, until fully cooked.
Remove the lid and let the chicken rest for a few minutes before serving over the spicy harissa chickpeas.