In a skillet over medium heat, cook the ground beef until browned, breaking it apart with a spoon. Drain excess fat if needed.

Stir in the taco seasoning along with some water according to packet instructions, then let it simmer for a few minutes.

In a large bowl, combine the seasoned beef, cooked rice, sour cream, nacho cheese sauce, cheddar, and mozzarella. Stir until well mixed.

Lay out a flour tortilla and spoon a generous amount of the filling into the center. Fold the edges and roll tightly to form a burrito.

In the same skillet, heat butter or oil. Once hot, place the burrito seam-side down and cook until golden brown and crispy. Flip and repeat on all sides.

Remove from heat, let sit for a minute, then slice in half and enjoy.