Combine panko, Parmesan, garlic powder, and a pinch of salt and pepper in a small bowl.
Place a chicken breast between two pieces of plastic wrap. Pound with a rolling pin, mallet, or heavy-bottomed pan until ½ inch thick. Season with salt and pepper. Repeat with remaining chicken breast.
Place chicken breasts on a lightly oiled baking sheet and brush tops with 4 T. sour cream. Press crust mixture into sour cream. Bake in oven until chicken is cooked through and crust is crispy, 12-15 minutes.
Prepare bagged salad and divide between plates and top with chicken. Serve with lemon wedges on the side for squeezing over.
Version II
Combine panko, Parmesan, all spices and butter in a small bowl.
Continue with remaining directions above.