For the chicken:
1) Position a rack in the middle of the oven and preheat to 220C/Gas 7. Season the chicken thighs generously with salt and pepper. Heat a large ovenproof skillet over medium-high heat, add oil, and heat until shimmering. Cook chicken skin side down until golden and crispy, about 8 mins. Turn chicken and brown for another 2 mins. Transfer chicken to a plate. Pour off 1 tbsp of the pan drippings and reserve; leave just enough oil in the skillet to evenly cover the bottom, discard the rest.
2) Add the fennel, onions, garlic, oregano, and red pepper flakes to the skillet and cook until the vegetables just begin to wilt, about 3 mins. Stir in the tomatoes and olives. Arrange the chicken, skin side up, on top of the vegetable mixture and bake, uncovered, until the chicken is cooked through, about 20 to 30 mins.
For the couscous:
1) Rinse the couscous in a fine mesh sieve under cold water until the water runs clear. Put couscous into a medium bowl and set aside. In a small saucepan add the chicken broth, reserved drippings, the 5g salt, nutmeg, cayenne, and black pepper and bring to a boil. Add the broth to the couscous and cover with plastic wrap and set aside until the liquid has been absorbed and the couscous is plump, about 5 mins.
2) Toast the pine nuts in a small skillet over medium-high heat, tossing in the pan until golden brown, about 2 to 3 mins. Add the orange zest, fennel fronds and parsley.
3) When ready to serve, fold the parsley mixture into the couscous and fluff with a fork. Mound the couscous on a warm serving platter and arrange the chicken around the couscous. Stir 30 to 45ml water or broth into the fennel mixture so they look glazed. Adjust seasoning and spoon fennel over the couscous and chicken; scatter the toasted pine nuts on top.