Hi,
I recently met the same problem and I search “chromedriver armhf” in google. I got the list of available releases:
https://launchpad.net/ubuntu/xenial/armhf/chromium-chromedriver
I take the version 72.3626.0.121 corresponding to my chrome browser on my Raspberry 3B+. After installation, It works on command line but not yet via sensor.
Keep debugging on this issue.