Is this menu supposed to be blocking (the code does not leave the switch case until the user has left the nested menu)?
In your original code it looks as if you were going to introduce a nested switch statement, but you omitted the switch statement itself - you only included the case statements. Hence it was considered as a (mangled) part of the outer switch, causing the error.
In a later copy of your code you added the switch statement but did not include the code to read the user input used to navigate within the menu or anything to cause the sketch to wait until that input arrived or cope if it did not arrive.