Insert a small iPod opening tool into the seam on the headphone jack side of the Nano, with the edge of the tool pointing toward the rear panel.

Gently enlarge the existing gap by pressing/wiggling the small iPod opening tool into the gap near each of the the two tabs attached to the rear case, pushing the clips toward the center of the Nano until both have been freed.

The large iPod opening tool is no longer needed to gain access to the left side of the iPod.

Repeat the same procedure listed in the previous step to free the three clips along the hold switch side of the Nano.

Insert an iPod opening tool into the gap near the top left corner of the Nano and work to free the three clips along the top edge of the rear panel.

After ensuring all tabs are free, separate the two halves of the iPod.

The rear panel is now free from the iPod.