Preheat oven to 375℉, and grease a large baking dish
Cook the onion in olive oil in a large skillet over medium heat until soft
Add ground beef, and cook until no longer pink, breaking it up as it cooks. Drain grease if needed
Stir in taco seasoning and 1/4 cup enchilada sauce until well combined. Remove from heat
Add a half cup enchilada sauce to the bottom of the baking pan
Place a tortilla on a flat surface, and spread a scant amount of enchilada sauce over the surface, using the back of a spoon
Add about a quarter cup each of the meat mixture and cheese to the middle of the tortilla
Roll the tortilla up and over the filling, and place seam side down in the baking dish
Repeat process until all tortillas and meat are used. If there is leftover meat, spoon it next to the enchiladas
Pour remaining sauce on top of the enchiladas, and brush it all the way to the ends of the tortillas
Top with remaining cheese
Bake for 20-25 minutes or until cheese is melted and sauce is bubbling all over
Allow to rest for about 5 minutes before serving