Cocos2D has many features for those looking to develop isometric games. Handling of z-ordering, and tile maps are all built into the engine.
I’ve found an excellent open source game example known as KnightFight from Loz Archer of an isometric 2D tile based action rpg using Cocos2D. The game features a player controlled character that you move around the map, collisions between the player and map objects, simple computer controlled enemies, and basic player improvement through leveling.
You can find the source code on Github here:
A pretty simple game, but everything within it is very well done so if you are looking to create a tile based isometric RPG with Cocos2D this is a good example.