There isn't much information about why the bar closed as their Facebook Page has pretty much removed all posts and their website was taken down.
There was an event posted on Facebook for the last night in business on April 30th and the description stated:
"Nick's House has been home to BROKEN for a while now and we are very sad to see this place close it's doors. However, we are lucky to have the opportunity to send Nick's out in style for it's last night open....."Another Facebook post from a band said they were playing the last Metal Monday at Nick's House the Monday before the bar closed.
Also, a few people commented on the original update to let me know that the bar was closing.
This is the fifth bar from season 4 (first set) of Bar Rescue to close and the Bar Rescue Updates Page has been updated with this information.
UPDATE - The building that housed Nick's House was demolished in 7/2016.