It's a surprisingly powerful and customizable editor. Just create a .nanorc file in your home directory and paste the following settings.

set titlecolor sage,black
set linenumbers
set tabsize 4
set breaklonglines
set softwrap
set atblanks
set guidestripe 80
set stripecolor brown,black
set indicator
set autoindent
set trimblanks
set whitespace "→·"
set zap
set positionlog
set historylog
set casesensitive
set multibuffer
set wordbounds
set wordchars "_-$"
#set mouse

bind ^H help main
bind ^G gotoline main
bind ^/ comment main
bind M-M findbracket main
bind M-] indent main
bind M-[ unindent main

Full nanorc documentation here.