Place the chicken thighs in a medium bowl. Add the rosemary, smoked paprika, salt and pepper, and toss to coat the chicken.
Heat 1 teaspoon of olive oil in large nonstick skillet set over medium-high heat. Add the chicken and cook for 2 minutes on each side. Transfer the chicken to a plate.
Heat the remaining 1 teaspoon of olive oil in the skillet. Add the onion and mushrooms, and cook until the vegetables are tender, 4 to 5 minutes.
Stir the quinoa and broth into the vegetables. Bring to a boil, then cover, reduce heat and simmer for 15 minutes. Nestle the chicken into the quinoa, and cook (covered) until the liquid is absorbed and the chicken is cooked through, about 15 minutes (total of 30 minutes).
Transfer the chicken to a plate. Stir the spinach into the quinoa. Serve with the chicken. Season to taste.