Preheat oven to 375 degrees F. In a large skillet, heat olive oil over medium high heat. Add the onion and cook until softened, about 3-4 minutes. Add the garlic and cook for an additional 2 minutes. Add the spinach leaves and cook until they are wilted and shrinks down. Stir in the lime juice, cilantro, green chiles, cumin, and chile powder. Remove from heat and stir in the sour cream. Season with salt and pepper, to taste.
To assemble, spread about 1/2 can of enchilada sauce in the bottom of a 9 x 13 baking dish. Fill each tortilla with about 1/3 cup of the spinach mixture. In a medium bowl, combine both kinds of shredded cheese. Sprinkle cheese over spinach mixture, about 3 tablespoons per enchilada. Roll up and place seam side down in the baking dish. When all enchiladas have been rolled and placed in the pan, top with the other 1/2 can of enchilada sauce and about 1/2 of the other can. We had some sauce leftover. Sprinkle remaining shredded cheese on top of enchiladas. Bake 20-30 minutes or until the cheese is melted, and the sauce is bubbling around the edges.
Garnish enchiladas with green onion, cilantro, and avocado, if desired. Serve warm.
Note-these enchiladas freeze well. Cool completely, without toppings, and place in a tupperware container. Reheat individual servings in the microwave when ready to eat! You can also freeze an entire pan and reheat in the oven!