The main difference is that Nitrobetting offers Sign Up and Reload bonuses up to 50 mbtc.
Aside from that there's also no minimum deposit based on the FAQ which is good since nitrogensports minimum is
BTC0.001 for both deposit and withdrawals.
This looks like a product manufactured on same industry coming to the market in the form of different brand products. Overall we may think the brand is different, but the product is the same.
They literally use the same providers that's why it's the same but there's a couple of improvements like the bonuses and the no minimum deposit i've mentioned above.
Curious to see if they have plans to introduce a reward system in the future since that's the current trend between their competitors.