Thank you. You don't need brackets if you follow my advice from Access Beginner Level 1 which is to NOT use spaces or other non-alphanumeric characters in your field names. You don't need brackets for:

=NZ(FirstName,"")

Whereas you would need brackets for:

=NZ([First Name],"")

So many people skip B1 because they already have SOME knowledge of Access, but I give all of my best fundamental pointers, tips, and rules in that class.