In a mixing bowl, combine the cooked shredded chicken, chopped spinach, ricotta cheese, half of the mozzarella cheese, garlic powder, onion powder, salt, and pepper. Mix until well blended.
Heat the olive oil in a skillet over medium heat. Lightly sauté the mixture for about 3-4 minutes until the spinach is wilted.
Pour half of the enchilada sauce into the bottom of a 9x13-inch baking dish, spreading it evenly.
Warm the corn tortillas in a dry skillet or microwave until pliable.
Spoon a heaping tablespoon of the chicken mixture onto each tortilla, roll them tightly, and place seam-side down in the baking dish. Repeat until all filling is used.
Once the tortillas are arranged in the dish, pour the remaining enchilada sauce over the top and sprinkle with the remaining mozzarella cheese.
Bake in the preheated oven for 20-25 minutes or until bubbly and the cheese is melted.
Remove from the oven and let rest for a few minutes before serving.
Drizzle with sour cream and garnish with fresh cilantro if desired.