Preheat your oven to 375°F (190°C). This ensures the chicken cooks evenly and the cheese melts beautifully.
Season the 4 boneless, skinless chicken breasts with salt and pepper on both sides. This simple seasoning enhances the overall flavor.
In a mixing bowl, combine the 15 ounces of enchilada sauce and the drained 14.5 ounces of diced tomatoes with green chilies. Stir until well mixed.
Spread a thin layer of the sauce mixture on the bottom of your baking dish. Place the seasoned chicken breasts on top, and then pour the remaining sauce mixture over the chicken.
Dollop the 8 ounces of sour cream over the top of the chicken and sauce. Use a spatula to spread it evenly for creamy goodness in every bite.
Sprinkle 1 cup of shredded Mexican cheese blend over the sour cream layer. This will create a deliciously gooey top once baked.
Cover the baking dish with aluminum foil and bake in the preheated oven for 30 minutes. Remove the foil and bake for an additional 10-15 minutes, or until the chicken is cooked through and the cheese is bubbling and golden.
Once baked, remove from the oven and let it rest for a few minutes. Garnish with chopped fresh cilantro and crumbled cojita cheese. Serve with tortilla chips or strips on the side for an extra crunch!