Setting backgroundColor of custom NSView

What is the process of drawing to NSView using storyboards for osx? I have added a NSView to the NSViewController. Then, I added a few constraints and an outlet.

Next, I added some code to change the color: import Cocoa

class ViewController: NSViewController {

    @IBOutlet var box: NSView!

    override func viewDidLoad() {
        super.viewDidLoad()
    }

    override func viewWillAppear() {
        box.layer?.backgroundColor = NSColor.blueColor().CGColor
        //box.layer?.setNeedsDisplay()
    }

    override var representedObject: AnyObject? {
        didSet {
        // Update the view, if already loaded.
        }
    } 
}

I would like to do custom drawing and changing colors of the NSView. I have performed sophisticated drawing on iOS in the past, but am totally stuck here. Does anyone see what I'm doing wrong?

The correct way is

class ViewController: NSViewController {

@IBOutlet var box: NSView!

override func viewDidLoad() {
    super.viewDidLoad()
    self.view.wantsLayer = true

}

override func viewWillAppear() {
    box.layer?.backgroundColor = NSColor.blue.cgColor
    //box.layer?.setNeedsDisplay()
}

override var representedObject: AnyObject? {
    didSet {
    // Update the view, if already loaded.
    }
}}