Font Patching with Font Forge

Only use this option if you want to patch a custom font that is not available from nerd fonts

Steps

brew install fontforge
git clone this repo
Copy the font file you would like to patch into the downloaded repo
cd <repo location>
fontforge -script font-patcher <path to font>
Wait for the script to finish and then open the newly created font file with Font Book (right click -> open with -> Font Book)
Click Install Font
Restart iTerm or Terminal and select the newly created font in preferences

Troubleshooting

You need to have python installed and correctly linked
This can be as simple as brew install python but if that is not working for you, try the steps outline here

Windows

If you are trying this on Windows, follow the installation instructions here