When prompting your users to fill in a form, it can be handy to sometimes help them out by filling in some of the information for them. You can do this by default values of course, but sometimes it needs to be more contextual.
For one solution I was working on, I had an issues list that I needed our users to populate as and when they encountered a bug, the issues would relate to an item that a workflow was running on, but the issue was being recorded on a separate list.
I built a link in the email the workflow would send them, prompting them to raise any bugs they found that looked like the following:
Then, with Nintex forms, open your control properties and in the Default Value field add the Inline Function "fn-GetQueryString(URL)".
This would produce the following results when set for Site URL column and the Status column in the screenshot below. Obviously, you could do an awful lot more with this.