In 10-inch skillet; cook beef over medium-high heat 5 to 7 minutes, stirring frequently, until thoroughly cooked; drain. Stir in water, 1 cup milk and the sauce mix (from Hamburger Helper box) until blended. Heat to boiling. Stir in uncooked rice (from Hamburger Helper box).
Reduce heat; cover and simmer about 25 minutes, stirring occasionally, until rice is tender.
Meanwhile, in small bowl, stir milk and topping mix (from Hamburger Helper box) 30 seconds; set aside. Slightly crush corn chips (from Hamburger Helper box); set aside.
Heat tortillas as directed on package. Spoon about 1/3 cup beef mixture down center of each warm tortilla; drizzle with cheese topping. Top with green onions, tomato and crushed corn chips. Fold bottom of each tortilla 1 inch over filling. Fold sides in, overlapping to enclose filling. Fold top over sides.