Problem 
In Nintex Workflow, workflows triggered by the same SharePoint list aren't automatically aware of each other. This makes it tricky to cleanly terminate "other" workflows when needed — for example, when enforcing a "latest run wins" scenario. 
 

Prerequisites 

1. Create dedicated tracking columns in your SharePoint list — one per workflow using the list.  
   • Name each column after its corresponding workflow. 
   • Type: Single line of text 
   • Important: 
     • Do not add these columns to the default view (uncheck the option when creating them). 
     • If you're deploying from Development → Production, make sure these columns also exist in Production, or your workflow will fail. 

Setup Instructions 

1. In each workflow, immediately after it starts, update the SharePoint list item:  
   • Write the current Workflow Instance ID to that workflow’s tracking column. 
2. When you want to use the “Terminate Workflow” action with “All except current one”:  
   • Loop through the tracking columns for the other workflows. 
   • For each:  
     • Check if there’s an existing instance ID. 
     • Use “Get Workflow Instance Details” to verify if that workflow is still running. 
     • If it is, call the Terminate Workflow action with that ID. 

Why This Works 
Since Nintex Workflow does not inherently know that workflows A, B, and C all belong to the same list item, this method manually tracks which workflow instances are active - giving you control to shut down any you don’t want to run anymore.