Anywhere Nano is accepted, just like every unit of money. There are various mechanism for doing so, including phone-based apps, Internet based payment gateways, and hardware systems.
If your question is rather on the current number of places which do accept this currency, probably the best place to look is online and Venezuela, which has been left without a local currency in effect.
Technology is easy. Technically creating a cryptocurrency is, more or less, Childs play. It's completely useless though unless people can actually use it.
It seems premature to declare your currency successful when no one can actually use it.
If your question is rather on the current number of places which do accept this currency, probably the best place to look is online and Venezuela, which has been left without a local currency in effect.