Combine all the filling ingredients, mixing well.
Preheat the oven to 400°. Spray 9 X 13 baking dish with cooking spray.
Brush each tortilla with a little enchilada sauce. Put about 3 tablespoons of filling down the center of each tortilla. Roll tightly and put in the baking dish seam side down. When all enchiladas are rolled, brush the tops with more enchilada sauce. Bake for 20 minutes.
Put the Velveeta, chilies if using, and milk in a microwave-safe bowl. Cook on high in 30-second bursts, stirring in between, until cheese is melted and the sauce is smooth.
Pour about half the cheese sauce down the middle of the enchiladas. Let them rest 10 minutes before serving. Serve the rest of the cheese sauce with the enchiladas, and garnish as you like.