León [1] is one of the few Nicaraguan cities with more attractions than you can see in a day. Plan on at least two to visit the museums [2] and cathedrals [3] of the city; another if you plan to hike a volcano [4], and another if you head to the shore [5].
Las Peñitas [6], Isla Juan Venado [7], Padre Ramos [8] and other points outside León require more effort to get to but are excellent destinations for those traveling on a slightly slower schedule. It’s worth slowing down in fact, so you can paddle boats through the estuaries and observe the wildlife (like nesting turtles on Juan Venado).
There is plenty to do, whether you come for two days or two weeks.
Links:
[1] http://www.moon.com/destinations/nicaragua/northwest-coast/leon
[2] http://www.moon.com/destinations/nicaragua/northwest-coast/leon/sights/museums
[3] http://www.moon.com/destinations/nicaragua/northwest-coast/leon/sights/walking-tour-leon
[4] http://www.moon.com/destinations/nicaragua/northwest-coast/near-leon/south-leon/volcan-momotombo-and-momotombito-island
[5] http://www.moon.com/destinations/nicaragua/northwest-coast/near-leon/beaches-west-leon
[6] http://www.moon.com/destinations/nicaragua/northwest-coast/near-leon/beaches-west-leon/las-penitas-beach
[7] http://www.moon.com/destinations/nicaragua/northwest-coast/near-leon/beaches-west-leon/isla-juan-venado-wildlife-reserve
[8] http://www.moon.com/destinations/nicaragua/northwest-coast/cosigueina-peninsula/jiquilillo-and-padre-ramos