Spouse's half-nibling's spouse.
half-co-nibling-in-law.
The grandchild-in-law of one's spouse's sibling.
My co-great-nibling-in-law is a good person.
The child-in-law of one's spouse's sibling.
My co-nibling-in-law is a good person.
The grandchild-in-law of one's parent-in-law's sibling.
My first co-cousin-nibling-in-law is a good person.