Heat olive oil in a skillet over medium heat.
Add the chicken breast to the skillet, cooking for about 6-7 minutes on each side, until fully cooked through.
Sprinkle the ranch seasoning mix over the cooked chicken, stirring to combine before removing from heat.
In a large bowl, combine the diced avocado, shredded lettuce, and diced tomatoes.
Warm the flour tortillas in a dry skillet for about 30 seconds on each side until pliable.
Layer the cooked chicken, the avocado mixture, and shredded cheese on each tortilla, then roll it up tightly.
Serve immediately with hot sauce on the side if desired.