Brown the ground beef and onion in a skillet over medium heat until beef is crumbled and no longer pink. Drain any fat and return skillet to oven. Sprinkle in the taco seasoning and water. Stir until combined and the water absorbs into the ground beef. Remove from heat.
Spread about 1/2 cup of the enchilada sauce on the bottom of a 9x13" casserole dish to evenly coat the bottom.
Add 1/3 cup of the ground beef mixture in a straight line to the center of each tortilla. Add about 1/4 cup of the shredded cheese and roll up tightly. Lay seam side down in the casserole dish. Repeat until the casserole dish is filled with the rolled enchiladas. If you have any remaining ground beef, sprinkle it over the top of the rolled enchiladas.
Spread the rest of the enchilada sauce over the top of the tortillas, making sure to coat each tortilla. Sprinkle the remaining cheese all over the top and bake for 20 to 25 minutes, or until the center is bubbly.
Top with your favorite toppings and enjoy!
FREEZING INSTRUCTIONS: Prepare these enchiladas as directed, but before baking cover tightly with foil and freeze for up to 3 months. When ready to bake leave foil on the enchiladas and bake at 375 degrees for 40 to 45 minutes. Center should be bubbly. Remove foil and bake an additional 5 minutes.