Warm the flour tortillas in a dry skillet or microwave for 15 seconds until pliable.

Lay the tortillas flat on a clean surface and spread 2 tablespoons of ranch dressing over the center of each.

Distribute the cooked chicken, shredded lettuce, cheddar cheese, tomatoes, and red onion evenly among the four tortillas.

Fold the left and right sides of the tortilla towards the center over the filling.

Starting from the bottom, roll the tortilla tightly upward to form a cylinder.

Secure with a toothpick if necessary or place seam-side down on a plate.

Slice diagonally in half and serve immediately.