Add this to your build.sbt:

libraryDependencies += "de.surfice" %%% "scalanative-cocoa-foundation" % "0.0.1-SNAPSHOT"
                       
addCompilerPlugin("org.scalamacros" % "paradise" % "2.1.0" cross CrossVersion.full)
                       
resolvers += Resolver.sonatypeRepo("snapshots")

Replace scalanative-cocoa-foundation with scalanative-cocoa-appkit if you want to use AppKit. However, it’s probably best to start with the template in that case (see below).

SNCocoa requires scala-native 0.3.2.