In 1-quart saucepan, heat 1 cup of the water, and the uncooked rice and topping (from Hamburger Helper box) to boiling over medium-high heat. Reduce heat; cover and simmer about 25 minutes or until rice is cooked and liquid is absorbed.
Meanwhile, in 12-inch nonstick skillet, cook beef over medium-high heat, stirring frequently, until brown; drain. Add remaining 1 1/4 cups water and sauce mix (from Hamburger Helper box). Cook about 4 minutes, stirring frequently, until mixture is thickened.
Meanwhile, in medium bowl, mix sour cream and cream cheese until smooth. Spread sour cream mixture in even layer on large platter. Top with beef mixture, followed by rice mixture. Top with lettuce, tomato, Cheddar cheese and corn chips (from Hamburger Helper box). Serve immediately.