It looks as though they removed the XIB-based project templates. You can still create new subclasses with accompanying XIB files though.
You can start from a XIB-only clean project with Xcode 8.3.
- create a new macOS cocoa app project
- right click the left column (files tree) and select "New File..."
- select "Main Menu" from the list then click "Next", then click "Create" on the dropdown view
- on left column move to trash two files using right click: Main.storyboard and ViewController.swift
- select the very first item of files tree to display target's general preferences
- find the "Deployment Info" section of your preferences, then change "Main Interface" menu value selecting "MainMenu.xib"
- almost done, now just select your xib then add an empty object to your xib then set its class to AppDelegate.