Apple has done an excellent job with the documenting the Swift programming language and I’ve been asked a couple of times about tutorials and so far by the best are on Apple’s own Swift Programming language page.
Here’s a tutorial from Matthijs Hollemans that takes a different approach to teaching the basics of the Swift programming language guiding you through the creation of a Candy Crush style match 3 game using Sprite Kit.
You’ll learn the basics of creating classes and functions, declaring variables, using arrays, dictionaries, conditional statements, and more in a fun by example way.
Here’s an image of the game built from the tutorial in action:
A nice tutorial for learning the basics of Swift and Sprite Kit.