1. Prepare the Beef Filling: In a large skillet, cook the ground beef over medium-high heat until it’s browned and cooked through. Drain any excess fat.
2. Add the finely chopped onion and minced garlic to the skillet with the cooked beef. Sauté for a few minutes until the onion is translucent.
3. Stir in the diced tomatoes, diced green chilies, ground cumin, chili powder, salt, and pepper. Cook for another 5 minutes, allowing the flavors to meld. Remove from heat and set aside.
4. Make the Sauce: In a separate bowl, mix the enchilada sauce and sour cream until well combined. This will be your delicious sauce for the sanchiladas.
5. Assemble the Sanchiladas: Preheat your oven to 350°F (175°C). Take each corn tortilla and spoon a generous portion of the beef filling into the center. Sprinkle some shredded cheese on top of the beef.
6. Roll up the tortilla tightly and place it seam side down in a greased 9×13-inch baking dish. Repeat this process with the remaining tortillas.
7. Pour the enchilada sauce mixture evenly over the rolled tortillas. Make sure they are well coated.
8. Sprinkle the remaining shredded cheese over the top.
9. Bake: Cover the baking dish with foil and bake in the preheated oven for about 20-25 minutes, or until the cheese is melted and the sanchiladas are heated through.
10. Garnish and Serve: Remove the foil and bake for an additional 5 minutes to lightly brown the cheese. Garnish with chopped cilantro and sliced jalapeños, if desired.
11. Serve: Serve your Beef and Cheese Mexican Sanchiladas hot. They are great with a dollop of sour cream and a side of guacamole or salsa.

Enjoy your delicious homemade sanchiladas with the rich beef filling and cheesy goodness!