How do you say I miss you in Native American language?

"Native American" is not a single language but very many. In addition, "how do you write" is a difficult question as the languages are very old but writing them is relatively new, so there is some inconsistency in spelling. A common usage is "Miigwetch", which means Thank You in Algonkian tongues such as Ojibwa and Cree; it's also sometimes spelled "Meegwich" and probably other ways as well. "Nya weh" means Thank You in Mohawk. In Oneida it's "Yaw Ko". And so on.