#BitcoinUnits

Most commonly, units of bitcoin are expressed in decimal exponents such as BTC ("bitcoins"), mBTC ("millibitcoins") and μBTC ("micro-bitcoin or bit ") and the rest more niche units are listed in the sheet...

https://en.bitcoin.it/wiki/Units

On the Bitcoin Wiki page, bitcoin units are presented following a decimal metric system, similar to standard SI units. The smallest unit listed is the satoshi, equal to 0.00000001 BTC.

If a hypothetical unit of nanobitcoin were to be introduced, it would logically fit in the scale just below the satoshi, which is 0.00000001 BTC. A nanobitcoin would represent 0.000000001 BTC, making it one-tenth the size of a satoshi and one hundred times smaller than a micro-bitcoin (0.000001 BTC).

So long story short. There's no such thing as a #nanoBitcoin

But yeah maybe one day on some side chain we'll get even smaller unit then satoshis and we can make nanoBitcoins #Finneys ;)