I'm not sure a baked version will ever completely compare with the crunchy shell of a deep-fried sandwich from a fast food restaurant, but thanks to a highly-seasoned panko breading, this sandwich is pretty darn close!
Preheat oven to 350°F. Place a wire baking rack on a baking sheet and spray liberally with cooking spray. Set aside.
Place each chicken breast between two pieces of plastic wrap. Using the flat side of a meat tenderizer or a glass, pound the chicken breasts until about ½"-¾" thick. Slice both chicken breasts in half to make four, sandwich-sized chicken pieces.
In a shallow dish, whisk together flour, salt and pepper. In a second shallow dish, whisk together red pepper sauce, milk and egg. In a third shallow dish, combine breadcrumbs, cayenne pepper, garlic powder, paprika and onion powder.
Dredge chicken pieces in flour mixture, followed by red pepper sauce mixture, and then finally, press into breadcrumb mixture. Shake off extra and place on prepared baking rack. Repeat with remaining pieces. Spray tops of chicken with cooking spray. Bake in preheated oven for 15-20 minutes or until chicken is browned and crunchy.
Meanwhile, combine yogurt, dijon and minced garlic in a small bowl. Spread evenly on each of four hamburger buns. Serve chicken on buns with tomato slices and lettuce leaves.