Display a portfolio tags individual post

Just in case you didn’t find an answer to this elsewhere, you actually use the_terms() in order to do that. https://codex.www.ads-software.com/Function_Reference/the_terms

For example:

the_terms( $post->ID, 'portfolio-tag', 'Tags:', " / " ); would be the function call.

‘portfolio-tag’ is whatever the id of the taxonomy is
‘Tags:’ is what you want displayed before the list
” / ” is the separator