This seems to be the same thing as your loop.

ALTER PROCEDURE [dbo].[uspNHistory]

-- Add the parameters for the stored procedure here

@NH_ID INT

,@N_ID INT

AS

DECLARE @CNID INT

,@CID INT

,@CA NVARCHAR(50)

BEGIN

-- SET NOCOUNT ON added to prevent extra result sets from

-- interfering with SELECT statements.

SET NOCOUNT ON;

-- Insert statements for thisLoop

INSERT INTO tblC2NHistory (

NH_ID

,C2NID

,CID

,N_ID

,CA

)

SELECT @NH_ID

,CNID

,CID

,@N_ID

,CA

FROM dbo.tblC2N

WHERE NID = @N_ID

END

I would recommend that whenever possible you name your columns more verbosely. The super short abbreviations make it incredibly hard to work with and incredibly easy to make mistakes. It is possible these are all primary keys or something but they could still stand some clarity. Just my 2¢.