In a mixing bowl, combine the shredded cheddar cheese, Monterey Jack cheese, and low-fat mozzarella cheese. Stir them together until well mixed.
Spray your nonstick skillet lightly with nonstick spray and place it over medium heat.
Take a tortilla and place a generous amount of the cheese mixture in the center. Fold the sides of the tortilla over the cheese, then roll it up tightly from the bottom to the top.
Once your skillet is heated, place the roll-up seam side down in the skillet. Cook for about 2-3 minutes or until the bottom is golden brown and crispy. Carefully flip the roll-up using your spatula, and cook the other side for another 2-3 minutes.
Once both sides are perfectly golden and the cheese is melted inside, remove the roll-up from the skillet. Let it cool for a minute, then slice it in half. Serve it warm with salsa, guacamole, or sour cream for dipping.
