1 (1 ounce) package dry ranch salad dressing mix (such as Hidden Valley Ranch®)
1 large egg
1 tablespoon milk
¾ cup plain bread crumbs
Preheat the oven to 350 degrees F (175 degrees C). Place butter in 9×13-inch baking dish and let melt in the preheating oven.
Slice chicken breast against the grain into thin strips.
Place ranch dressing mix in a small bowl. Whisk egg and milk together in a second bowl. Place bread crumbs in a third bowl.
Dredge each chicken strip in ranch dressing mix, then coat in egg mixture and cover with bread crumbs; arrange in the prepared baking dish.
Bake in the preheated oven for 15 minutes. Gently turn chicken pieces over and bake until an instant-read thermometer inserted into the center reads 165 degrees F (74 degrees C), about 15 minutes longer.