Preheat the oven to 350°F (175°C). Line a baking sheet with parchment paper or lightly grease it with cooking spray.
In a large bowl, combine the room-temperature cream cheese, taco seasoning, shredded Pepper Jack, and shredded cooked chicken; stir until evenly mixed.
Place about 1/4 cup of the chicken mixture in the center of each tortilla.
Fold the two sides of the tortilla over the filling, then roll from one open end to the other to enclose the filling and place seam-side down on the prepared baking sheet.
Repeat with remaining tortillas and filling, arranging chimichangas on the sheet so they are not touching. Brush each chimichanga with melted butter.
Bake for 15–20 minutes, or until the chimichangas are golden brown and crispy.
Remove from the oven and top with sour cream, guacamole, and pico de gallo as desired before serving.
