This code work just fine it has no errors.

CREATE TABLE Mytest (id INT, x XML)

INSERT mytest

VALUES

(1, CAST('1200' AS XML))

,...

Using SQL 2012

-- Msg 195, Level 15, State 10, Line 5

-- 'NVARCHAR' is not a recognized built-in function name.

-- The TRY_Convert function requires 3 argument(s).

SELECT TRY_CONVERT(NVARCHAR(1), 234523)

Did I miss something?