Preheat your oven to 350°F (175°C).
Cook the egg noodles according to package instructions until al dente.
In a large bowl, mix the cream of mushroom soup and milk until smooth.
Add the drained tuna, frozen peas, chopped onion, garlic powder, and black pepper to the bowl.
Stir in the cooked noodles and half of the shredded cheese.
Pour the mixture into a greased 9x13 inch baking dish.
Top with the remaining shredded cheese and crushed potato chips.
Bake in the preheated oven for 25-30 minutes, until bubbly and golden.
Remove from the oven and let it cool for a few minutes before serving.
Enjoy your delicious tuna noodle casserole!