You said you want to mine XBT (which is BTC) only, but Nicehash mines different coins.
The Baikal miner is made for DASH mining, not BTC, it cannot mine SHA-256. Also, all GPUs are obsolete for mining.
Nicehash does not mine BTC, but it mines altcoins and then converts them.

For Bitcoin mining, the best option is the Antminer S9.
For altcoin mining, including using Nicehash, post in this section: https://bitcointalk.org/index.php?board=160.0