I would like to create a chart on customer service dashboard that shows the number of open vs closed orders for that day

Also, I am trying to create a formula that will show the status of the order being either open or closed.

I currently have the formula below to show when the status of the order is closed

If(not IsNull([Engineering Complete Date]),"Closed",[Status Update])

This formula works correctly to show the closed status in the pie chart, however the other field in the pie chart just show "blank" instead of "open". On the pie chart it still shows the amount of orders that are still open. It is just confusing to people to have it be called "blank" instead of "open"

How do I add onto this formula to show the open orders?

Thanks!