Noun
Someone's nephew's wife.
Someone's niece's wife (where same-sex marriage is recognised).
Someone's sibling's daughter-in-law.
Someone's brother's daughter-in-law. (fraternal niece-in-law)
Someone's sister's daughter-in-law. (sororal niece-in-law)
Someone's spouse's sibling's daughter-in-law.
Someone's wife's brother's daughter-in-law.
Someone's wife's sister's daughter-in-law.
Someone's husband's brother's daughter-in-law.
Someone's husband's sister's daughter-in-law.
(rare) Someone's spouse's niece.
Someone's husband's niece. (Usually called a niece.)
Someone's wife's niece. (Usually called a niece.)
Source: en.wiktionary.org