Preheat the oven to 350 degrees. In a medium bowl, mix 1/2 cup of ranch dressing with the jar of salsa Verde. Spoon a thin layer of salsa verde into the bottom of the dish, set aside.
Heat a a skillet or pan on medium/high heat, pour 1 tablespoon of oil into the pan and allow to heat for minute. While the skillet is heating coat the chicken breasts with salt and pepper then place on the skillet. Cook for 4-5 minutes on each side.Remove from the skillet and allow to rest for at least 3 minutes before shredding.(If you are using per-cooked chicken please skip this step)
After shredding the chicken, combine the chicken, 1 cup of cheese, and ranch salsa Verde mixture. Spoon about 1/3 cup mixture down the middle of a tortilla. Fold sides over and place seam side down in prepared baking dish. Top with the remaining salsa Verde mixture and 1 cup of cheese. Allow to cook for 15-20 minutes or until the cheese is bubbly and the edges are golden.