Begin by preheating your oven to 350°F (175°C). This will ensure that your casserole cooks evenly.
If you haven’t already, cook and shred your chicken breasts. You can boil, bake, or even use leftover rotisserie chicken for convenience.
In a large mixing bowl, combine the Greek yogurt, skim milk, and salsa. Stir until well blended, creating a creamy base for your casserole.
Add the shredded chicken, corn kernels, and diced red bell pepper to the yogurt mixture. Gently fold everything together until all the ingredients are coated.
Start by spreading a thin layer of the chicken mixture on the bottom of your baking dish. Place a layer of corn tortillas on top, cutting them if necessary to fit.
Continue layering: add another layer of the chicken mixture followed by a layer of tortillas. Repeat until you run out of ingredients, finishing with a layer of the chicken mixture.
Sprinkle the reduced-fat cheddar cheese evenly over the top layer of the casserole.
Cover the baking dish with aluminum foil and bake for 30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the cheese is bubbly and golden brown.
Let the casserole cool for a few minutes before slicing into portions. Serve warm, and enjoy your Skinny Chicken Tortilla Casserole!