[Quoth]

I admit Nano is not much like WS:
Simpler than Vi or Emacs?

File handling
Ctrl+S Save current file
Ctrl+O Offer to write file ("Save as")
Ctrl+R Insert a file into current one
Ctrl+X Close buffer, exit from nano

Editing
Ctrl+K Cut current line into cutbuffer
Alt+6 Copy current line into cutbuffer
Ctrl+U Paste contents of cutbuffer
Alt+T Cut until end of buffer
Ctrl+] Complete current word
Alt+3 Comment/uncomment line/region
Alt+U Undo last action
Alt+E Redo last undone action

Search and replace
Ctrl+Q Start backward search
Ctrl+W Start forward search
Alt+Q Find next occurrence backward
Alt+W Find next occurrence forward
Alt+R Start a replacing session

Deletion
Ctrl+H Delete character before cursor
Ctrl+D Delete character under cursor
Alt+Bsp Delete word to the left
Ctrl+Del Delete word to the right
Alt+Del Delete current line

Operations
Ctrl+T Execute some command
Ctrl+J Justify paragraph or region
Alt+J Justify entire buffer
Alt+B Run a syntax check
Alt+F Run a formatter/fixer/arranger
Alt+: Start/stop recording of macro
Alt+; Replay macro

Moving around
Ctrl+B One character backward
Ctrl+F One character forward
Ctrl+← One word backward
Ctrl+→ One word forward
Ctrl+A To start of line
Ctrl+E To end of line
Ctrl+P One line up
Ctrl+N One line down
Ctrl+↑ To previous block
Ctrl+↓ To next block
Ctrl+Y One page up
Ctrl+V One page down
Alt+\ To top of buffer
Alt+/ To end of buffer

Special movement
Alt+G Go to specified line
Alt+] Go to complementary bracket
Alt+↑ Scroll viewport up
Alt+↓ Scroll viewport down
Alt+< Switch to preceding buffer
Alt+> Switch to succeeding buffer

Information
Ctrl+C Report cursor position
Alt+D Report word/line/char count
Ctrl+G Display help text

Various
Alt+A Turn the mark on/off
Tab Indent marked region
Shift+Tab Unindent marked region
Alt+N Turn line numbers on/off
Alt+P Turn visible whitespace on/off
Alt+V Enter next keystroke verbatim
Ctrl+L Refresh the screen
Ctrl+Z Suspend nano