Nintex form validation based off another fields input

You are on the right track. Try the Condition below in your Validation rule. It works for me.

and(isNullOrEmpty(C4C OPP ID),greaterThanOrEqual(EstimatedQuoteAmount,25000))

@bamaeric Thank you for such a quick response!

I tried the solution you mentioned above and I am still not receiving a pop up message letting users know that the C4C OPP ID# box is required at that $ limit:

Note: I did try using {Self} instead of ‘C4C OPP ID’, but both produced the same result.

I did not receive the error message that I put into that box, nor did it stop me from submitting in this preview mode.

Is it possible that something on the SharePoint side is preventing me from using this validation or should Nintex override any SharePoint rules?

What are the names and field types of the C4C OPP ID# and Estimate Quote Amount fields?

Did you just copy my condition formula or did you add the controls to the formula via the Named Controls tab?

Below are the results I see from the form in Preview mode using the configurations in my screenshots:

@bamaeric 

In SharePoint, these are the names and format: 

I manually typed the formula and chose the controls from the ‘named controls’ tab.

You’re correct in that controls in the formula should come from the Named Controls tab. Could you add screenshots of the Control Settings of the two controls so I can see their configurations (Name, Connected to, etc.)?

Does anything happen when you enter a number less than 25000?

@bamaeric 

C4C OPP ID Control settings:

EstimatedQuoteAmount Control Settings:

I do not receive anything different/new when entering in a number less than 25000 either.