There sure is. There's Safari for iPhone, Chrome for Android, and Internet Exploder for anyone unfortunate enough to have spent money on a Windows Phone.
Sarcasm aside...in the modern day of fully-fledged web browsers, high-res screens, and speedy mobile connections, there's no need for a dedicated "app" for a website.
I honestly find such apps irritating, because they only restrict functionality. And there's nothing more obnoxious than being asked if I would like to download a website's app when trying to actually navigate to it with my web browser. No, I would not like to download the Official XDA App. I would like to use my modern web browser to view the complete site. And I would like to not be interrupted by questions while trying to do so.
The only thing a NICO app would do differently would be presenting everything with big text and big buttons. Pinch-zoom solves that problem in any browser.
I use NICO very frequently on my phone, but I've never felt the need for a NICO-specific app.
