That worked perfectly! Thank you!

I like the results. Cleaner. Easier to read, easier to copy/paste the nicename when needed for specific @mentions in posts. 

Let's try this. Put this code in a PHP snippets using Code Snippets plugin or in the functions.php file of your current active WordPress theme, delete all caches and check it:

add_filter( 'wpforo_member_nicename', function($nicename){
    return str_replace(array('(', ')'), '', $nicename);
});

Can you share with me how to do this?

I have the "Code Snippets" plugin, is there a line or two of code I can add to it?

I appreciate you considering adding this filter for me and anyone else interested in doing the same thing.

I'm sorry but that's not possible. We'll add a filter hook in next version to allow you filter and remove unnecessary characters.

such as using ::first-letter and ::last-letter.

I tried different combinations and never seemed to get the right combination of selector and ::xx-letter.

Thanks!