In a saucepan, melt butter over medium heat, mix in flour to create a roux, and cook until it’s bubbly. Gradually add chicken broth and bring the mixture to a boil, stirring often.
Sprinkle the remaining cheese on top of the enchiladas and bake in the preheated oven for 20 minutes, or until the cheese is melted and the sauce is bubbly around the edges.