Finally figured out how to change device priority in QoS settings on nighthawks

You have to check mark the box beside each device on the QoS page, then "edit" at the top of the screen is no longer greyed out. Click edit, and you can change a single device's priority. Painful because when you apply the updated priority for that device, the router goes through a lengthy update, and you have to repeat for any other devices you want to change (it would be nice to be able to check multiple devices and change them in groups, but no possible).