Looking at the USA Network's upcoming schedule, it appears that NXT will be moving for at least one Wednesday night due to the NHL playoffs.
The September 2nd episode of NXT looks like it has been moved from Wednesday and will air on Tuesday, September 1st at 8 PM Eastern. If you looking at the schedule it appears that the NHL has a playoff game in their normally scheduled time slot.
The playoffs are set to conclude no later than October 4th and it's currently unknown if this will affect more weeks of NXT on Wednesdays. As of this writing the September 2nd episode is the only that appears to have been moved from it's normal time slot. No official announcements have been made by the USA Network or WWE at this time.