In a skillet over medium-high heat, sauté onions until translucent and tender, approximately five minutes.
Add shredded chicken and 3/4 of the red enchilada sauce to the skillet, and stir until well combined. Set aside. Slice rolls in half, to create a top and bottom bun. Please bottom buns on a nonstick baking sheet.
Play's enchilada chicken mixture on the bottom buns, and top with shredded cheese, and then the remaining enchilada sauce.
Place the tops of the rolls on the sliders.
Brush with melted butter, cover with aluminum foil and bake for 20 minutes.
Remove foil and bake for another five minutes, or until shredded cheddar cheese has melted thoroughly.