We have the amazing Lake Nicaragua/ Cocibolca in Granada, Nicaragua (also known as "Sea of Sweet Water"), which is the second biggest lake in the American continent. (See picture to the left.)
In addition to that, nearby we also have Apoyo lake, which is in the crater of a sleeping (dormant) volcano. (See picture below.)
We do not have near by rivers or waterfalls. But we do have rivers and waterfalls in other places of Nicaragua.