Nano currency is going to use new kind of PoW instead some kind of version blake-2b to increase antispam security. As SafeNetwork have also free transactions it might be good tool to protect network if spam will be issue. The main target was reduce transactions per second on high powerful HW like ASIC servers, but remain easy to solve on mobile and office desktop.
Edit: Add point of attack
https://github.com/tromp/cuckoo/blob/master/doc/Nano_PoW