Short answer...no, not currently.  Here are a couple of posts that discuss this exact issue.  In the first one there is a proposed work around.

Populate task id as soon as the task is created

Issue Retrieving Flexi Task ID

Flexi Task Problems

There is also a request on the User Voice site that you can vote for to have this feature added. Populate task id as soon as the task is created

Thanks. I voted for it. Its surprising that Nintex is overlooking this since 2014. They should have fixed this bug long time ago. 

If you are referencing the taskID in the same action or in a parallel action, then Brendan is correct; it cannot be done.

My workaround, as stated in some of the examples that Brendan provided above, is to use a parallel action and in one branch put your task, and in the other, use a pause step and whatever actions you need. The pause step will allow the system to create the task, thus generating the ID that you can then reference within the workflow.

I do this if there are customization's to the notification or if assigned to multiple users/groups and using a Request Data action.

Example:

Thanks for the response.. I was able to achieve it using parallel actions. In one branch create the flexi task and assign a variable to the task name. Make sure to populate the task name(with times tamp at the end of the name) in the variable before the parallel branch action. In the second branch pause for one min and query the task list using the task name and use the id to generate the URL.

Hey Jesse, 

I've tried your solution. On the branch that's parallel to the task, I pause for 5 minutes, then update some task metadata of the workflow task list, I'm not touching any outcome, completed dates, or anything, I'm just updating some fields that explain more about the task such as Project Name and Contract number...ect..  For some reason the task always gets completed as a "Response no longer required". however the workflow stays in limbo/ yellow forever pending something, the update is yellow state and the workflow task on the diagram is is also yellow and when I hover on it, it says "No Longer required" , I'm the only one assigned the task and I didn't complete it and again the task on the list says "Completed"... It is driving me crazy and I don't know -for the life of me- what is going on??? 

The task ID is captured: 

Update task metadata: 

Help!! 

Never mind...  I just got it to work with a query List of the task form, and I queried the name of the task. The ID is not getting assigned, even after a pause. I tried logging it into the history log after he pause, waiting even 15 min didn't do it... I guess it is the old 2013 env. that could be the issue..