Preheat oven to 400 degrees F. Cover a baking sheet with aluminum foil and mist with cooking spray.

In a bowl, stir together chicken, cheese and salsa until well-mixed. Spoon approximately 1/2 cup of the mixture into the center of a tortilla. Fold in the sides, then roll the tortilla from bottom to top to make a chimichanga (burrito) shape. Place the chimichanga seam side down on the baking sheet. Repeat with remaining tortillas and filling mixture, then brush the outside of the tortillas with melted butter.

Bake for 25 minutes until tortillas are golden brown. Remove and serve immediately, with additional toppings if desired.