In a large bowl, combine the cooked chicken and ranch dressing. Mix well until the chicken is evenly coated. Season with salt and pepper to taste.
Heat the olive oil in a skillet over medium heat.
Place a tortilla in the skillet and cook for about 30 seconds on one side until warm. Flip the tortilla.
On the warmed side of the tortilla, layer 1/4 of the chicken mixture, followed by 1/4 cup of shredded lettuce, 1/4 cup of diced tomatoes, and 1/4 cup of shredded cheddar cheese.
Fold in the sides of the tortilla and then roll it up tightly from the bottom to the top.
Repeat steps 3-5 for the remaining tortillas and filling.
Once all wraps are assembled, return them to the skillet, seam side down, and cook for an additional 2-3 minutes on each side until golden brown and crispy.
Remove from the skillet, slice in half, and serve warm.