I need to update the taxonomy field on nodes with the term from a new vocabulary. I could accomplish this easily in Drupal 6, and haven't been able to find a method in Drupal 7. I am looking for a UI based solution like VBO.
There is no native support for this in VBO, due to the way that Taxonomy has now been moved into the fields API. There is an outstanding task that is being worked on to bring Taxonomy actions back into VBO.
In the meantime, you can try this patch against VBO 7.x-3.0-beta2, kindly posted by erik2e.