Preheat oven to 375°F (190°C).
In a large skillet, cook ground beef over medium heat until no longer pink. Drain excess fat.
Add taco seasoning and water, stir well, and simmer for 3-4 minutes.
Spread a spoonful of enchilada sauce over the bottom of a 9x13 inch baking dish.
Divide the beef mixture evenly among tortillas. Sprinkle with cheese, roll up, and place seam-side down in the baking dish.
Pour remaining enchilada sauce over the enchiladas and top with remaining cheese.
Bake uncovered for 20-25 minutes, until cheese is melted and bubbly.
Garnish with chopped onion and cilantro before serving if desired.