Preheat an oven to 350 degrees F (175 degrees C). Grease a 2-quart casserole.
Bring water to a full rolling boil in a pot.. Cook the egg noodles in the boiling water, stirring occasionally, for 3 minutes; remove from heat, cover, and let stand until the noodles are tender, about 10 minutes. Drain.
Stir the noodles, onion, sour cream, chicken soup, ham, and Swiss cheese together in a large bowl. Season with salt and pepper. Spoon into the prepared casserole. Sprinkle the top with bread crumbs.
Bake in the preheated oven until the casserole is bubbling and the bread crumbs have browned, about 40 minutes.
