In 12-inch nonstick skillet, cook beef and onion over medium-high heat, stirring frequently, until beef is thoroughly cooked; drain.
Add tomatoes, water, Italian seasoning and contents of seasoning packet from soup mix; mix well. Heat to boiling. Break up noodles; stir in noodles and beans.
Return to a boil. Reduce heat to low; cover and simmer 5 minutes or until noodles and beans are tender, stirring occasionally.