How to addObject as NSMutableArray in NSMutableArray in swift

If I am not wrong you want to add an object of NSMutableArray in another NSMutableArray you can do it by following code

var myArray : NSMutableArray = ["Hello"]
var arrayOfArray : NSMutableArray = [myArray]

// Insert more arrays with insertObject or addObject

arrayOfArray.insertObject(myArray, atIndex: 0)
arrayOfArray.addObject(myArray)

//Retrive
var newArray:NSMutableArray = arrayOfArray[0] as NSMutableArray
println("\(newArray)")

For Swift 3:

var myArray : NSMutableArray = ["Hello"]
var arrayOfArray : NSMutableArray = [myArray]

// Insert more arrays with insertObject or addObject

arrayOfArray.insert(myArray, at: 0)
arrayOfArray.add(myArray)

//Retrive
var newArray:NSMutableArray = arrayOfArray[0] as! NSMutableArray
print("\(newArray)")

Here is an example:

var mutableArray: NSMutableArray = []
var nestedMutableArray: NSMutableArray = []
mutableArray.addObject(nestedMutableArray)
var retrievedNestedMutableArray:NSMutableArray = mutableArray[0] as NSMutableArray