In a large skillet, brown the ground beef together with the chopped onion over medium heat until fully cooked.
Stir in the green chilies, enchilada sauce, and cream cheese, allowing the mixture to melt and combine thoroughly.
In a 9x13-inch baking dish, create layers starting with a base of Fritos corn chips, followed by the seasoned meat mixture, and then a generous sprinkle of shredded cheese. Repeat the layers if desired.
Place the dish in a preheated oven at 350°F and bake for 15 to 20 minutes, or until the cheese has melted and is bubbling.
Upon serving, garnish each portion with shredded lettuce, diced tomatoes, salsa, and a dollop of sour cream according to preference.