Bring chicken broth to a boil in a saucepan. Stir quinoa into the broth and bring again to a boil; reduce heat to medium-low, cover, and simmer until quinoa is tender and broth has been absorbed, 15 to 20 minutes.
Stir scallions and 1 1/2 teaspoons lemon juice into the quinoa.
Mix paprika, cumin, onion powder, black pepper, cayenne pepper, and sea salt together in a small bowl; rub onto chicken breasts to season completely.
Prepare a large skillet with cooking spray and heat over medium-high heat.
Lay chicken breasts into the hot skillet, cover skillet with a lid, and cook until chicken is no longer pink in the center and the juices run clear, about 7 minutes per side. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).
Blend avocado, yogurt, 1 1/2 teaspoons lemon juice, and garlic powder in a food processor until smooth.
Spread quinoa onto a serving platter. Arrange chicken breasts onto the platter. Drizzle avocado cream sauce over the chicken breasts.
