Preheat your oven to 425°F.
Boil salted water in a large pot and cook egg noodles per package instructions until al dente. Drain and set aside.
In a large bowl, mix the condensed cream of mushroom soup and milk until smooth.
Add the drained tuna, frozen peas, and 1 cup shredded cheddar cheese to the soup mixture. Stir until well combined, season with salt and pepper.
Gently fold the cooked noodles into the tuna mixture until evenly coated.
Transfer the mixture into a 9x13-inch baking dish and spread evenly.
Evenly scatter the crushed potato chips and the remaining 1/2 cup of shredded cheese on top of the casserole.
Bake in the preheated oven for 15-25 minutes, or until the casserole is hot and bubbly.
Remove from the oven and let stand for a few minutes before serving. Enjoy!