Niece-in-law (only spouse's niece).
My niece-by-marriage is a good person.
by QWP998756 October 15, 2021
Get the niece-by-marriagemug. Spouse's nibling's wife.
My niece-by-marriage-in-law is a good person.
by NSBC968755 February 25, 2023
Get the niece-by-marriage-in-lawmug. 
Get the niece-by-marriagemug.