great-grandnephew-in-law

1- Great-grandnibling's husband.
2- Spouse's great-grandnephew.

My great-grandnephew-in-law is a good person.

great-grandnephew-by-marriage-in-law

Spouse's great-grandnibling's husband.

My great-grandnephew-by-marriage-in-law is a good person.