Preheat the oven to 375.
Add ground beef and onions to a pan over medium high heat.
Sautè until cooked, then drain the fat.
Return the fat, add the spinach, a drizzle of the enchilada sauce and taco seasoning. Cook until spinach is wilted.
Add about 1/2 cup of the enchilada sauce to the bottom of a baking dish.
Spoon the beef mixture into the tortillas, wrap them up and place the seam side down in the baking dish. Do this for all 8 tortillas.
Top with cheese.
Bake for about 20 minutes, or until the cheese is nice and melty.
Top with pico de gallo.