See Data Option in Line Chart

I created a line chart based on work due [NEXTDUEDATE]; chart works as expected, however, when I go to see the data, I see the [NEXTDUEDATE] value. 

My question is can I set it up to where it displays a different value from the Table; I want it to display [PMNUM], because that is what helps tell the person what they have, not just a date. 

Greatly appreciate any help!  :-)