When comparing SpriteKit vs Nez, the Slant community recommends SpriteKit for most people. In the question“What are the best 2D game engines?” SpriteKit is ranked 54th while Nez is ranked 89th. The most important reason people chose SpriteKit is:
Easy to access in Xcode.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Built-in in Xcode
Easy to access in Xcode.
Pro Awesome performance
One of the most efficient frameworks. If you need to build an iOS game, this is the best solutions.
Pro Active community
The community is very active, so if you ask for help you'll get it relatively quickly.
Pro Open source
Completely free, no need to pay for licenses.
Pro Cross-platform development thanks to the use of mono and xamarin
Nez is built on top of monoGame and can be used the make games for many platforms (Windows, Linux, Mac, Android or IOS).
Cons
Con Restricted in apple ecosystem
This is an Apple technology and its use is restricted to iOS and OSX systems.
Con Just a framework
Meaning there's no visual scene designer so you'll have to write your own.