Set your oven to preheat at 375 degrees Fahrenheit.
Beat the egg in a bowl until well blended.
Remove any excess fat from the chicken breasts, then slice them into strips approximately 2 inches wide.
In a large zip-lock bag, combine the panko breadcrumbs with salt and pepper.
Lightly spray a baking sheet with non-stick cooking spray to prevent sticking.
Dip each chicken strip into the beaten egg, ensuring it is fully coated, then place it into the zip-lock bag with the panko mixture. Seal the bag and shake well to coat the chicken evenly with the breadcrumb mixture.
Arrange the breaded chicken strips on the prepared baking sheet in a single layer.
Bake in the preheated oven for 15 to 20 minutes, or until the chicken is fully cooked and the coating is golden and crispy.