A few weeks ago Nova Launcher began parading around one of their upcoming new features known as Icon Normalization, a feature which would give the ability to users to have Nova auto scale their icons to appear as they matched in size, if they so desired to do so. At the time Nova said the feature would be coming to their beta version of the app in the near future, and around a week later which was on September 15th they toggled the feature on for those users who were on the beta version of the application. Today through the 4.1 version update of the app, Nova makes the feature available to anyone who uses the launcher alongside a few other changes.
If you're unsure of Icon Normalization, there's a reason to Nova's decision to implement it. Icons are usually vastly different with some being boxy and some being round, while others have shapes or lines protruding in various directions. With so many variables for any number of icons a user might have from installed apps on their device, they can appear to be different sizes even if they're all scaled at the same percentage. You can see the stark contrast of these differences in the screenshots below, which displays how square icons for example might look as if they're bigger than round icons when in fact they're not. This is where Icon Normalization comes in and if toggled on, it will scale the icons that look "overly large" to a smaller size so they visually appear to match up better with the others.
Alongside the Icon Normalization, Nova has also added in some other changes to update version 4.1. There is now an option for a Marshmallow style search bar both with the grayscale and color options, and there is now support for runtime permissions in Marshmallow. Of course, users can also expect some performance improvements and stability improvements as Nova has been given the bug fix and optimization treatment. If you're already updated to the latest version of the app, simply head into the Nova Settings, navigate to the Look and Feel section and there will be a toggle for this option in that menu.