The standard NULLIF case expression is supported, generating SQL of the form NULLIF (expression, expression). It must be supplied exactly two arguments. The entire NULLIF expression will automatically be enclosed in parentheses if it is not part of an expression and not already enclosed in parentheses. When dragging a Null If into a variable, the following tree element is created.
Variable Creation > Input > Variables: SQL Elements pane - Case > Null If

Columns and/or other expressions can be moved over the (empty) branches of the tree.
NULLIF can be used in place of the non-standard Teradata specific command NULLIFZERO. For example, NULLIF(column1, 0) is equivalent to NULLIFZERO(column1).
There are no special properties for the Null If function.