Ambiguous use of subscript

You have to tell the compiler what the intermediary object is in the line

After the statement 

jsonResult["levels"]!

 the compiler does not know what kind of object he is dealing with. You have to tell it that is an 

NSArray

 or something else:

Of course you should additionally make sure that you can actually do all that casting and that the objects inside the json are really of the expected type.