/* Using a temporary variable */
<<set _where to either("kitchen", "garden", "cellar")>><<goto _where>>
/* Using a backtick expression */
<<goto `either("kitchen", "garden", "cellar")`>>
Beyond that, if you're using the <<goto>> within a <<link>> macro, then you don't need it in the first place as <<link>> natively offers the ability to forward the player to a passage—no <<goto>> needed.
Comments
You'll need to use either a temporary variable or a backtick expression (see: Passing an expression as an argument, near the top) to pass the result of the either() function.
For example:
Beyond that, if you're using the <<goto>> within a <<link>> macro, then you don't need it in the first place as <<link>> natively offers the ability to forward the player to a passage—no <<goto>> needed.