I am assuming you are talking about Nintex Forms. There is a setting that you can check to resize on runtime. This will allow for some adjusting, but you can also show/hide panels based on controls that are selected or certain values.
Do you have something specific you are attempting to do?
Resize on runtime is checked on the panel.
We have 3 controls in the panel, the third sometimes is hidden depending on some condition.
We'd like to have the panel resized when the third field is hidden.
I would suggest that you would need to put the conditionally hidden control in it's own panel and hide the panel when the condition is met. I'm not sure that a panel will resize to a smaller height - it more pertains to increasing size to incorporate dynamically larger objects.