It's not currently possible to disable the orange LED lights indicating the microphone has been switched off.
Please leave feedback for the Google Nest team requesting that this is added in a future update.
Cathal_S, thanks for sharing your insights.
Pzd, we’re always trying to improve our user’s experience, but at this moment, turning off the orange LED of the Google Nest speakers isn’t possible. Sending your feedback can help us a ton, feel free to send one using the guide shared by Cathal_S.
Let us know if you have other questions or concerns otherwise, we'll go ahead and lock this thread after 24 hours.