Preheat your oven to 400°F. Lightly coat a 9×13-inch glass or ceramic baking dish with non-stick cooking spray and set it aside.

Place the boneless, skinless chicken breasts flat on a clean cutting board. Using a sharp chef's knife, slice them horizontally to create thin, even cutlets. Uniform thickness ensures all the chicken pieces cook through at the exact same rate without drying out the edges. Pat the meat dry with a paper towel.

In a medium mixing bowl, combine the sour cream, mayonnaise, dry ranch seasoning packet, garlic powder, and grated parmesan cheese. Whisk firmly with a fork until the ingredients emulsify into a thick, uniform, and highly aromatic seasoning paste.

Arrange the dried chicken cutlets in a single, flat layer across the bottom of the prepared baking dish. Avoid overlapping the pieces excessively so the hot air can circulate evenly.

Using a silicone spatula or the back of a spoon, spread the creamy ranch mixture evenly over the top of each chicken cutlet, making sure to coat the surfaces entirely to create an insulating moisture shield.

Scatter the shredded mozzarella cheese uniformly over the top of the ranch layer across the entire dish. Dust the surface lightly with a pinch of smoked paprika to add a beautiful color contrast during baking.

Place the dish uncovered on the middle oven rack and bake at 400°F for 22 to 25 minutes. The chicken is finished the exact moment an instant-read digital thermometer inserted horizontally into the thickest part of the meat registers 165°F.

For an extra-crispy finish, turn the oven to Broil for the final 2 minutes, watching closely until the top cheese layer turns entirely melted, bubbly, and takes on beautiful golden-brown patches.

Remove the dish from the oven and let the chicken rest undisturbed for 5 minutes before serving. This brief resting window allows the hot meat fibers to relax and reabsorb their internal savory juices. Garnish with fresh chopped chives and serve warm alongside steamed vegetables or over a bed of hot rice.