Half-first cousin’s grandchild.
My half-first great-cousin-nibling is a good person.
First cousin's great-grandchild.
My first great-great-cousin-nibling is a good person.
Child of their maternal first cousin with the paternal first cousin or double-first cousin’s child.
My double-cousin-nibling is a good person.
Nibling is a word to describe both Nieces and Nephews at the same time.
Ay, what's up niblings? You guys are playing Minecraft? Mind if i join you?