If you'd like to read my individual review of each products you can click HERE for the NARS Orgasm Illuminator, and HERE for the NYX Born to Glow Liquid Illuminator.
When I did a heavy swatch, NOI is peachier and NYX BTGLI paler. However, because both are sheer and are intended for highlighting, once blended they are almost identical. Personally, I think the way they look once blended is very hard to tell the difference so I would say NYX BTGLI is a good dupe. Other than being a good dupe, it also lasted longer than the NARS Orgasm Illuminator at a much more affordable price.
What do you think? I'm definitely in favor of the NYX Illuminator.