In a large bowl, whisk eggs, cottage cheese, 1 cup jack cheese, parmesan cheese, 1/2 teaspoon salt, and nutmeg until well blended.
Coarsely chop artichoke hearts. With your hands, squeeze as much liquid as possible from spinach. Stir artichokes and spinach into egg mixture.
Spread mixture level in a buttered shallow, rectangular 2 1/2- to 3-quart casserole. Sprinkle remaining 1 cup jack cheese evenly over the top.
Bake in a 350° regular or convection oven until custard is firm to touch in the center, 25 to 40 minutes. Let stand about 10 minutes, then cut into portions. Add more salt to taste.