Your first cousin's nephew is be the child of your first cousin's sibling, who is also your first cousin. So your first cousin's nephew would be your first cousin, once removed. Similarly, your second cousin's nephew is your second cousin, once removed, and so forth.
cousins.
Your child and your nephew are first cousins. Your child and your great nephew are first cousins, once removed.
Your son and your nephew are First Cousins. The children of your nephew and the children of your son are Second Cousins to each other.
Your nephew and your daughter are first cousins to each other.Your nephew's son and your daughter are first cousins, once removed, to each other.
Your nephew and your daughter are first cousins to each other. Your nephew's son and your daughter are first cousins, once removed. Your nephew's son and your daughter's child would be second cousins to each other.
Your great nephew and your granddaughter are second cousins to each other.
Your grandson and your great nephew are second cousins to each other.
Your uncle's grandchildren are your first cousins, once removed. They and your grand children are your second cousins, once removed
Your child and your great nephew's parents would be first cousins. Their children would then be second cousins. And if they have children, they will be third cousins.
A great great grandchild and a great great nephew of the same person are third cousins, once removed.
Your nephew and grand nephew may be parent and child. In not, then they are First Cousins, Once Removed.
Your daughter and your nephew are first cousins. His daughter is your daughter's first cousin, once removed.