Q:

How to direct the output of OPENROWSET() to an argument of an INSERT statement?

Context
I have ~32.25 million, 2KB sensor binary data files (amounting to 32.25E6*2/(1024^3) = 61.5 GB) of data that I'd like to put into a Microsoft SQL database table (Microsoft SQL Server 2014). The table is defined using: 
CREATE TABLE station_binaries (
   StationID int,
   StationName nvarchar, 
   Timestamp datetime2(7), 
   InstrumentNumber int, 
   Folder nvarchar, 
   Filename nvarchar, 
   Ensemble varbinary(MAX)
)

where Ensemble stores 2 KB of data. I'm writing a T-SQL query to test-insert a record into that table. Once successful, I will programmatically insert data into the table using Python and pyodbc.
Problem Statement
Per this advice, I tried to create a similar query and encountered the error: 

Msg 8152, Level 16, State 4, Line 2 String or binary data would be
  truncated. The statement has been terminated.

while trying to execute: 
INSERT INTO GCOOS.dbo.station_binaries (StationID, StationName, [Timestamp], InstrumentNumber, Folder, [Filename], Ensemble)
    VALUES (
        42861, 
        'DeepwaterNautilus', 
        DATETIME2FROMPARTS(2005,5,2,0,3,0,0,0), 
        0,
        'C:\Users\mtran\Desktop\...\ndbc_data\_42861_Deepwater_Nautilus\2005\05\02\', 
        '428610200505020003.bin',
        (SELECT * FROM OPENROWSET(BULK 'C:\Users\...\42861_Deepwater_Nautilus\2005\05\02\428610200505020003.bin', SINGLE_BLOB) result)
    )

I think it has to do with the syntax of the SELECT subquery that calls OPENROWSET(). The subquery itself executes OK on its own: 
SELECT * FROM OPENROWSET(BULK 'C:\Users\...\42861_Deepwater_Nautilus\2005\05\02\428610200505020003.bin', SINGLE_BLOB) result

0x7F7F7F0500081...

Solution
PeterHe's suggestion resolved the error. I changed the database table declaration so that all nvarchar read nvarchar(MAX):
CREATE TABLE station_binaries (
   StationID int,
   StationName nvarchar(MAX), 
   Timestamp datetime2(7), 
   InstrumentNumber int, 
   Folder nvarchar(MAX), 
   Filename nvarchar(MAX), 
   Ensemble varbinary(MAX)
)

A:

Ensemble varbinary should be  Ensemble varbinary(max).

