I just tested it out with my LC Gateway board and had great results using the infrared sensor track with LionChief!
I had a hunch this was going to be fine but it's still fun to see two of my projects working together to give a better experience with otherwise out of the box hardware.
This was all done without modifications to any Lionel hardware. Although I would like to make the the IR transmitter board small enough to fit inside a LionChief or TMCC locomotive. For now it rides in a box car behind the loco.
As a reminder my LC Gateway is the part that is bridging the legacy system to LionChief. I didn't really mention it in the video.