Heat a skillet over medium heat and brown the ground chuck, breaking it apart as it cooks. Once fully cooked, drain any excess grease and add the diced onion and taco seasoning blend.
Stir and cook for 2-3 minutes until the onions soften. Add the refried beans and mix well until fully combined. Stir in the hatch chilies and cook for another 2-3 minutes, then remove from heat.
Heat a cast iron skillet over medium heat and toast tortillas on both sides until golden brown. Sprinkle shredded jack cheese on one side of the tortilla, add the beef mixture, and fold it in half. Cook for another 1-2 minutes per side until crispy and the cheese has melted.
Garnish with fresh pico de gallo and serve with sour cream or guacamole on the side. Enjoy!