According to Hinduism, the are 4 yugas, Satya, Treta, Dwapra and Kali come in that order and then cycle. The belief is, that as the Yugas progress from Satya to Kali, the human life span decreases by an order of magnitude with each yuga, declining from 100000 years in satya yuga to a mere 100 years in Kali.
The Treta yuga is supposedly 1,296,000 years long and the Dwapra yuga is supposed to be 864,000 years long. So, obviously, Nana is not from the Treta yuga but one is still left to wonder how old he really is. Any guesses?
You can read Lavanya's take here.