I am new to using Nintex Forms and I’d like to be able to invalidate user entries if they meet a certain criteria (i.e. if entry is in the form of a letter and number (X1, X2, X3, etc)) How can I create a rule to do so?
Solved
Creating form entry rules using wildcard characters
Best answer by SimonMuntz
Hi
I think it would be easier to to write a rule around the format you want and not the format you don’t want.
In a control’s configuration you can set the validation to regular expression and then write a regular expression to match the format you want. Anything outside of that would error.
Example:

Enter your E-mail address. We'll send you an e-mail with instructions to reset your password.
