In a food processor or blender, combine the mayonnaise, buttermilk, lime juice, ranch dressing mix, cilantro, salsa verde and garlic. Pulse to combine. Add hot sauce to taste. If possible, refrigerate for several hours to allow the flavors to meld and combine.
Heat the oven to 425ºF. Line a baking sheet with foil and spray lightly with nonstick cooking spray.
Place the cream cheese in a medium microwave-safe proof bowl. Microwave for 20 to 30 seconds, or until easy to stir. Add in the salsa verde, lime juice, chili powder, cumin, onion powder and garlic powder. Add the chicken, cheese, cilantro and green onions; stir to combine.
Wrap 4 tortillas in a damp paper towel and microwave for 20-30 seconds, or until soft and pliable.
Place 2-3 tablespoons of the chicken mixture down the center of the tortilla, keeping it about ½-inch from the edges, then roll up. Place seam side down on the prepared baking sheet. Repeat with the remaining tortillas and filling.
Spray the rolled tortillas lightly with cooking spray, then sprinkle with kosher salt. Place the pan in the oven and bake until the tortillas are crisp and the edges have browned, 15-20 minutes.
Let the flautas cool for 5-10 minutes, then serve with the Creamy Cilantro-Lime Ranch Dressing.
