Heat 1 tablespoon of cooking oil in a large skillet over medium heat.
Add the ground beef to the skillet, breaking it apart with a cooking spoon. Cook until the meat is browned, about 5-7 minutes.
Drain excess fat if necessary, and stir in the taco seasoning, salt, and pepper. Mix well and cook for another 2 minutes.
Pour the nacho cheese sauce over the beef and stir until well combined and heated through, about 2-3 minutes.
Warm the flour tortillas in a tortilla warmer or microwave briefly until soft and pliable.
Lay a tortilla flat and spoon a generous portion of the cheesy beef mixture in the center.
Top with shredded lettuce, diced tomato, diced onion, and jalapeños if desired.
Add a dollop of sour cream on top if using.
Fold in the sides of the tortilla and roll it tightly to enclose the filling. Repeat with the remaining tortillas and filling.
Serve immediately, optionally wrapped in aluminum foil for easier handling.