Suggestion to use sudo -e.

[cmdremily]

Using sudo -e (e for edit) instead of sudo nano has some benefits: It will use the user's preferences to pick an editor (nano by default on Pi IIRC) but it also copies the file to a temporary location and edits it there and then copies the edited copy back once you exit. This means that spurious saves do not affect the file being edited, and autosaves etc are not saved next to the target file, keeping your config directory clean.

[EricZimmerman]

nano is clearly the best choice and superior editor here...

/Runs away