Preheat the oven to 400 degrees F. Spray a 9-by-13-inch baking dish with cooking spray; set aside.
In a large bowl, combine chicken, cream cheese, 1 ½ cups shredded cheese, green chiles, and ½ cup Buffalo sauce, stirring until well combined. Stir together the butter, remaining Buffalo sauce, and heavy cream in a medium bowl.
Microwave the tortillas in batches until warm, softened and foldable, about 30 seconds. Keep warm between damp paper towels.
Spoon ½ cup of the chicken mixture down the middle of each tortilla and roll up. Place them side by side, seam-side down, in the prepared pan. Pour the hot sauce mixture over the tortillas. Sprinkle with the remaining cheese and bake 15-18 minutes, or until cheese is melted and bubbly.
Sprinkle with blue cheese or drizzle the ranch dressing over the enchiladas, then garnish with cilantro or green onions. Serve with more Buffalo sauce, if desired.