Season chicken thighs, making sure to rub the seasoning and herbs over all the pieces.
Set a nonstick skillet on high heat. Once hot, spray the skillet with olive oil, then add the chicken thighs. Sear on each side for 3 minutes to make the outside crispy and brown, then remove the thighs from the skillet and set aside. No worries if the thighs have not finished cooking.
Reduce the heat to medium, then add olive oil, onion and garlic. Caramelize and brown the onion for 1 to 2 minutes.
Add the pearl couscous to the skillet to toast, and mix around in the skillet, ensuring the couscous is covered in oil. If desired, sprinkle in the smoked paprika now.
Toast for 1 to 2 minutes, then add chopped red chard (or greens) and mushrooms. Cook until the chard begins to slightly wilt and soften, about 2 minutes.
Pour in the chicken stock and bring to a simmer. Add chicken back to skillet. Reduce the heat to low-medium and cover and cook for 12 to 15 minutes, or until the pearl couscous is plump and the majority of the liquid has been absorbed. (Note: it should not be soupy, rather saucy.)