You will need some data about your HD key. Don't share the results, but reference this command for the following steps.
chia keys show
Grab the Fingerprint value for your key set. You will also need the keypath to your Pool Public key, e.g. (m/12381/8444/1/0). You will drop the parentheses and the leading m/ as shown below.
chia keys sign -f [fingerprint] -t [hd_path] -d [message] (sign a message with a private key)
# Working Example