There is an issue with the Bittrex link on CoinMarketCap, it has been like this for about 2 weeks.
If you go Nexus
https://coinmarketcap.com/currencies/nexus/#charts ,click on Markets, then NXS/BTC on Bittrex is not working, they still have old ticker as well.
Trex are dragging their feet. Support tickets have been raised but they are taking their time changing the ticker, Cryptopia made the change real quick.