Cook the chicken breasts until fully cooked, then shred them using two forks.
Warm the tortillas in a skillet or microwave until pliable.
Lay a tortilla flat on a clean surface.
Spread a layer of ranch dressing on the tortilla.
Add a handful of shredded lettuce in the center.
Layer shredded chicken on top of the lettuce.
Add sliced tomatoes, avocado, and red onion on top.
Sprinkle shredded cheese over the vegetables.
Season with salt and pepper to taste.
Fold the sides of the tortilla inwards and roll it tightly from the bottom up.