Preheat oven to 350 degrees.
Put potato chips in a Ziploc bag, and crush until they are crumbs.
Slice the onion into 1/2-inch-thick chunks, and separate the rings.
Arrange cheese strips inside the onion rings.
Repeat, alternating with the mozzarella and cheddar cheese.
Dip the onion rings in flour to coat.
Then dip them in the beaten egg.
Thoroughly coat the rings in potato chip crumbs.
Bake for 15 minutes.
Enjoy with tomato sauce or ketchup.