I am using Nintex 2013.
I have a Nintex form with 3 people picker fields: Approver1, Approver2, Approver3. (Approver1 is a required field).
What I want is: if Approver3 has a vaule, then Approver2 must also have a value.
I tried a Validation rule on Approver3 but it doesn't work: not(isNullOrEmpty({Self}) && isNullOrEmpty(Approver2)
What is wrong with my syntax?