Nemp can not only manage files, but also a list of web radio stations that you listen to regularly. However: Nemp is first and foremost an mp3 player, not a radio player. The function is included, but the focus is not on it.
In the tree view, web radio stations are displayed alongside files. You can edit this list and add new stations via the menu Media Library→Manage Webradio Stations. You can freely choose the name of the station. As URL you should enter the address of the station. Very often you will get it on the respective web page - usually you will find a link there that ends in .pls or .m3u. You must enter this link in the URL field.