Set the EDITOR and VISUAL environment variables to nano.
If you use bash on macOS, this is easiest done by editing your ~/.bash_profilebashrc file and adding the two following lines:
export EDITOR=nano export VISUAL="$EDITOR" to the bottom of the file. If the file does not exist, you may create it. If Note that macOS users should probably modify the ~/.bash_profile file instead, as the abovementioned file is not used by default when starting a bash shell on this system.
If you use some other shell, modify that shell's startup files instead (e.g. ~/.zshrcfor~/.zshrczsh` for zsh).
You should set both variables as some tools use one, and others may use the other.
You will need to restart your terminal to have the changes take effect.