Line baking sheet with aluminum foil.
Preheat oven to 400.
Place rack over foil and set aside.
In a shallow bowl, beat egg until blended.
Add water and beat until blended. Set aside.
Crush potato chips in food processor or place in zippered bag and use rolling pin to crush.
Transfer chips to another shallow bowl and set aside.
Split breasts lengthwise and pound to about 1/2" thickness.
Dip each piece of chicken in egg mixture making sure to coat.
Allow excess egg to drip off.
Place in chips. Sprinkle more chips over top. Gently press, then turn and repeat on other side. Shake off excess. Repeat with remaining chicken.
Place chicken on prepared pan.
Bake for 35 minutes.