IIF statement with multiple conditions

Question

Consent:

IIf([consents].[decision]=1,"grant",
    IIf([consents].[allowbreaktheglass]=0,"deny""Default"),
    IIf([consents].[AllowBreakTheGlass]=1 AND [consents].[Decision]=0,"emergency only"))

IIF statement is returning an error:

The expression you entered has a function containing the wrong number of arguments

Criteria for consents are Grant, Deny and Emergency only.

Answer 1

It's not 100% clear what you are trying to accomplish with your Nested IIF statement, however you are simply missing one failure argument, the following may be what you want:

Added 'Error?' for the last failure argument, as well as moved the 'Default' into the failure of the first clause.

Consent: 
    IIF([consents].[decision] = 1, 'grant',
        IIF([consents].[allowbreaktheglass] = 0, 'deny',
            IIF([consents].[AllowBreakTheGlass] = 1 AND [consents].[Decision] = 0,
                'emergency only', 'Error?')) 'Default')