Stay away from nanopool and monero mining, there is high difficulty. You can mine more XMR with other pools. Second reason, nanopool became more like megapool - it's too big for network.
This is not correct for the size of nanopool ....see here:
http://minexmr.com/pools.htmlBut right:
Here are some pools with their difficulty........ and nanopool has the highest and static difficulty
Nanopool: Share difficulty is static and equal to 120000
dwarfpool: 100000 for high-end CPU and GPU-Rigs
minexmr: Difficulty: 35000 Description: SSL port for Claymore
monero-crypto-pool.fr: Difficulty: 50000 Customs Difficulty Accepted: Append +DIFF Mining Address Description: SSL Port Stratum