In a 1-quart casserole dish, place a large layer of chips.
Drain the tuna and using a fork to break up the tuna, add it to the casserole.
Spoon the mushroom soup over the tuna and chips.
Add the mozzarella cheese and some of the cheddar.
Spoon the sour cream over the cheese.
Carefully mix everything together, making sure that it is evenly mixed throughout.
Sprinkle the remaining cheddar over the top.
Cut the butter into pieces and distribute over the top of the cheese.
Put into the preheated oven and cook for 20 minutes.
Notes
Make this your own by putting in your favorite potato chips.If you make this from homemade mushroom soup, you will need to thicken it considerably by adding flour. It should be the same consistency as canned mushroom soup.
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