Preheat the Oven: Set the oven to 350°F to ensure even cooking.
Cook the Onions: Heat olive oil in a medium-sized pan over medium heat. Add diced onions and sauté until softened and lightly browned. Transfer to a bowl and set aside.
Brown the Beef: In the same pan, cook the ground beef over medium-high heat until browned. Drain any excess grease and reduce the heat to medium.
Combine Ingredients: Stir in the cooked onions, taco seasoning, and 1-2 tablespoons of chipotle peppers in adobo sauce (or just the liquid for a milder flavor). Add chicken stock and scrape the pan to incorporate all the flavorful bits from the bottom.
Melt the Cheese: Add half of the shredded cheese to the pan and stir gently until it melts, creating a creamy beef mixture. Remove the pan from heat.
Prepare the Baking Dish: Spread 2 tablespoons of enchilada sauce evenly on the bottom of a baking dish.
Fill the Tortillas: Place 3-4 tablespoons of the beef mixture into the center of a tortilla. Roll tightly and place seam-side down in the baking dish. Repeat until the dish is filled with tortillas snugly placed side by side.
Top and Bake: Pour the remaining enchilada sauce over the rolled tortillas and sprinkle with the rest of the shredded cheese. Bake for 20 minutes until the cheese is melted and the dish is bubbly and hot.
Finish with Toppings: Garnish with fresh cilantro and serve with your favorite toppings like sour cream, pico de gallo, guacamole, or pickled jalapeños for added flavor.