Due to the new episodes that aired we now know that Sokka did inherit the mantle of chief of the Southern Water Tribe from Hakoda. This would mean that any children that Sokka had would inherit the title as well. But as we know after Sokka died Unalaq in conjunction with the Southern Council of Elders became the new leaders of the Southern Water Tribe, so does this mean Sokka didn't have any children? The one theory I have is that Sokka and Suki had a daughter and she became a Kyoshi Warrior and decided to live on Kyoshi Island, which is why we haven't seen any of Sokka's kids. He may have also had a son who decided he didn't want to be chief and followed his own path.