Using a view result as allowed_options in a text(list) field
Here's what I ended up with...

function hnbuilder_fheq_allowed_values(FieldStorageConfig $definition, ContentEntityInterface $entity = NULL, $cacheable){
    $node = \Drupal::routeMatch()-&gt;getParameter('node');
    //kint($node-&gt;bundle());
        if ($node instanceof \Drupal\node\NodeInterface) {
            $thisnid = $node-&gt;get('nid')-&gt;value;
            if($node-&gt;bundle() != 'qualification'){
                $nid = $node-&gt;get('field_qualification')-&gt;target_id;
                }
        }
        $args=[$nid];
        $values = [];
        $view = Views::getView('outcomes');

        if (is_object($view)){
            $view-&gt;setArguments($args);
            $view-&gt;setDisplay('default');
            $view-&gt;execute();
            foreach($view-&gt;result as $rid=&gt;$row){
                foreach ($view-&gt;field as $fid =&gt; $field ) {
                    $values[$rid][$fid . '-value'] = $field-&gt;getValue($row);
                    $my_options[$values[$rid]['field_fheq_code-value']] = "[".$values[$rid]['field_fheq_code-value']."]- ".$values[$rid]['field_fheq_description-value'];
                }
            }
        return $my_options;
    }
}