Is it possible to find the serial of the last connected device (iPod Nano) in itunes?

It is possible to get it from your computer if it was backed up using iTunes. The following quotation is from iOS: How to find the serial number, IMEI, MEID, CDN, and ICCID number

If you can access your computer, but not your device:

1. Open iTunes.
2. Open Preferences. (In Mac OS X, choose iTunes > Preferences. In Windows, choose Edit > Preferences.)
3. Click the Devices tab.
4. Position the mouse over a backup to display the serial number of the backed-up device. iPhone and cellular iPad models also display the IMEI/MEID and Cellular Data Number:
   

iTunes will only show the serial number for iOS devices backed up using iTunes (and the iPod nano is not an iOS device). For alternative ways to find the serial number, see:

On your iPod packaging

If you still have the original packaging for your iPod, you can find your serial number on the barcode label that's affixed to the packaging.

On your iPod invoice or receipt

Some retailers may include the serial number of your iPod on the receipt.

Online at My Support Profile

If you used your Apple ID to register or purchase your iPod, you may find the serial number listed in My Support Profile (available in the United States and Canada). Log in with your Apple ID and find your iPod in the My Products box on the main page:

From iPod: How to find the serial number.