I have two issues with the My Workflow tasks. First, I have a lot of tasks that are completely blank except for the Workflow name. I don't know how to fix those.
Second, I do not have a default sorting option on my webpart settings.
First of all you need to give us a little more information. What is this workflow for? Show us the set up of the task actions in the editor.
I also recommend splitting this into two separate questions. Your second question looks more like a Sharepoint question, not Nintex.