By default, the platform does not have this option. You can use the following CSS code:

Please follow the steps below:

1. Go to BuddyBoss > Theme Options

2. Under Custom Codes, enable CSS

3. Append the following:

#profile-edit-form .field_nickname input { pointer-events: none; }

4. Save changes.

This CSS code will make the Nickname field uneditable. 

Note: Any modifications are considered as custom work already. Know more about our Support policy here: https://www.buddyboss.com/support-policy/