There's a lot of reasons to have less hashrate on pool, it's not easy to have exactly 100% os hashrate on miner and pool
You can try to change the serve on Nicehash
But you can mine directly on Binance, and it's good, I use Nicehash too, but I put 50% of my rigs on Binance ETH
Go to:
https://pool.binance.com/Create your worker, put the config on your miner, and you're ready to go, you'll mine on Binance