In 10-inch nonstick skillet, cook beef over medium-high heat, stirring frequently, until brown; drain. Stir in 1 cup of the milk, the hot water, sauce mix and uncooked rice (from Hamburger Helper box). Heat to boiling, stirring occasionally.
Reduce heat. Cover; simmer about 20 minutes, stirring occasionally, until rice is tender. Meanwhile, heat oven to 350°F.
Cook chiles directly on grate of gas stove about 5 minutes, turning with tongs or fork to cook all sides of skin OR heat heavy cast-iron skillet over medium-high heat; place chiles in pan, turning to cook skins evenly. Place chiles in food-storage plastic bag 5 minutes. Peel chiles under cold water. Open on one side; remove and discard seeds.
Fill each chile with rice mixture. Place in ungreased 13x9-inch glass baking dish.
Bake 13 to 15 minutes or until chiles are soft. Meanwhile, stir remaining milk and topping mix in bowl. Top baked chiles with topping mixture, and sprinkle with corn chips (from Hamburger Helper box).