In a large pot with boiling salted water cook egg noodles until al dente. Drain.
In a large bowl combine the cooked egg noodles, cream of mushroom soup, evaporated milk, tuna, grated cheese and chopped onion. Pour into a greased 1.5 litre casserole dish. Sprinkle the top with the crumbled potato chips and the paprika.
Bake in a preheated 220 degree C oven for 15 to 20 minutes.