Preheat the oven to 350 degrees F. Make the kugel: Brush a 4-quart shallow baking dish with margarine. Bring a large pot of salted water to a boil. Add the noodles and cook as the label directs. Drain well, then transfer to the prepared baking dish. Add the margarine and stir to melt and coat the noodles.
Beat the cream cheese and 2 tablespoons apricot nectar in a large bowl with a mixer on medium speed until smooth. Add the sugar, then the eggs, one at a time, beating well after each addition. Add the milk and the remaining apricot nectar; beat until smooth and creamy. Pour the mixture over the noodles; stir to coat.
Make the topping: Combine the cornflakes, melted margarine and sugar in a medium bowl. Sprinkle on top of the noodle mixture and bake until just set in the center, about 1 hour. (If the topping is golden but the kugel is not yet set, turn off the oven and keep the kugel inside up to 20 more minutes.) Let cool 20 to 30 minutes before serving.