A quick search will turn up a ton of results, both in the Corona forums and abroad. Here’s an interesting one using isometric maps. Here’s a github page for the continued support of Lime within Corona.
I’d suggest checking out Dusk, which is a “_fully featured game engine for Corona SDK. It’s designed to help you “weed out” extra code for level creation and let you focus on the game mechanics, instead of the level makeup.” _Getting the map done is like a tenth of the problem; making your game mechanics operate within the world you’ve created is the harder part, and Dusk helps you do that.
http://forums.coronalabs.com/topic/42355-dusk-engine/