I would advise withdrawing all of your coins stored on Nitro ASAP. There is a fork coming tomorrow. It's a segwit2x fork to make transactions faster and cheaper and will probably be pretty popular.
I can tell you from bitter experience that they will delay a withdrawal request for about 24 hours if a fork snapshot is coming. I would not wait if you want your segwit2x btc coins.
Thanks for the advise, but I don't think they'll have any plans on disabling/delaying their withdrawals unless they put up an announcement and there was no complaints about withdrawing when the second fork happened. From my experience after the changes in their fees the withdrawals are a lot faster than it used to be. If there was a delay in withdrawals it's because of the amount of requests they receive in a short amount of time.
I tried to withdraw coins 16 hours prior to the bitcoin gold snapshot and it didn't go through until 24 hours later. I would not recommend waiting but it's up to you. It's just a snapshot which is occurring tomorrow, not a hard fork, so there is no reason that withdrawals should be an issue.
The point is, if you want to get your BT2X coins, withdraw your BTC from Nitrogensports.eu ASAP