Here are some symbols and footprints I created for a project that used the Arduino Pro Mini. Perhaps you can use them as starting points for your own symbols and footprints to fit the Nano.
Arduino_Pro_Mini.kicad_mod (9.4 KB)
Arduino_Pro_Mini_Sparkfun.kicad_mod (19.1 KB)
Arduino_Pro_Mini.dcm (450 Bytes)
Arduino_Pro_Mini.lib (4.9 KB)
Sorry, I don’t have 3-D models for these.
WARNING!
I discovered that Pro Mini modules from different vendors had different footprints! Verify that the footprint you use matches the parts you buy!
Dale