I don’t own Nars Midnight Express but Propaganda seems like a pretty good dupe to me. It is a beautiful translucent dark blue jelly that looks smooth and deep in two coats.
The polish applies almost by itself the first couples of times, but after a while it may turn a bit gooey, but nothing that a drop of thinner can't fix. I was a bit disappointed by the wear though. Illamasqua usually delivers top quality products, but this polish starts chipping after 3 or 4 days on my nails.
I avoid wearing it too often because it seems that it could stain nails if not applied over a very good quality base coat. I also find it quite difficult to remove without making a mess, even with a good polish remover it tends to transfer on the cuticles.