xcode - Copy asset catalogue to another project

First create the (empty) asset catalogue in your new project, In your new project click the target, and in the editor under 'App icons' click the button for 'Use asset catalogue'. Make sure the 'also use for launch images' is checked.

Now go out to the finder, and open two windows - one with your new project and one with the source project from which you're copying the asset catalogue.

In the source project, find the Images.xcassets folder. Option-drag it into the new project folder so that it will replace the empty one you just created in Xcode.