It depends how the line-breaks are encoded within the source data.
Line-breaks encoded as a carriage-return (ASCII code 13) followed by a line-feed (ASCII code 10) will display as expected.
For anything else, you'll need to replace the line break with
vbCrLf
:
=Replace(First(Fields!n1.Value, "GetAll"), Chr(13), vbCrLf)