The cost of the btc transactions from nicehash to your wallet eat into your earnings. I would recommend mining eth or whatever altcoin you prefer over nicehash.
How often does it pay out and how much is the fee?
Payouts for balances less than 0.1 to external wallet 4%
Payouts for balances greater than or equal to 0.1 BTC to external wallet 3%
Payouts for balances greater than or equal to 0.001 BTC to NiceHash wallet 2%
Once per day for NiceHash wallet unpaid balances, greater than 0.001 BTC.
Once per day for external wallet unpaid balances, greater than 0.1 BTC.
Once per week for external wallet unpaid balances, greater than 0.01 BTC.