To load the selected values from a taxonomy field, you can use the get_field function like so:
$selected = get_field('taxonomy_field_name');
I just looked at the get_posts documentation and the following is very useful:
Note: The category parameter needs to be the ID of the category, and not the category name.
Note: The category parameter can be a comma separated list of categories, as the get_posts() function passes the 'category' parameter directly into WP_Query as 'cat'.
So, with that in mind, please edit your taxonomy field and select ‘ID’ as the return format setting. Then you can use the following code: