If then for calculated date column

I am simply trying to display a date column based on a condition using calculated column.  Return value is date and time and date only format.

=IF([Event type]="Trade Show",[Start Date Time]+1,IF([Event type]="Vendor Expo",[Start Date Time]+1,[Start Date Time]))

I get an error when using the above formula.  If I use "=[Start Date Time]+1" then it work fine, but when using the IF then statement it gives an error.

Suggestions?

Thank you!