Here's a link that will allow you to calculate and compare gear ratios, or gear inches for a large selection of internal hubs, and also compare to derailleur systems. It's very useful and easy to used, with the various hubs listed on a drop down menu. Note: for single chainrings and sprockets, enter them in the first (left) box.

BTW- the link doesn't list a 5s Nexus, nor can I find a reference to one anywhere (didn't look hard), so are you sure that's what the bike is supposed to have?