Chief Charles Renatus Hicks - is he related to me

Charles Renatus Hicks was the son of a Cherokee woman and a white man named Nathan Hicks who also had a white family. An 18th cousin would be long before there were any Cherokee records, so your relationship must be through the white Hicks family.

You
→ Elva Alicia Nunez Terrazas
your mother → jose Antonio Nunez Lara
her father → Jose Antonio Nunez Rivera
his father → Jose Macario Nunez Jaquez
his father → Maria Dolores Jaques Garcia
his mother → Jose Maria Jaques Pinon
her father → Juana Clara Pinon y Martinez
his mother → Maximo Pinon
her father → Marcos Pinon De Acosta
his father → christoval Santiago Pinon Mendosa
his father → Ana De Mendoza y Sanchez De Ortega y Alarcon
his mother → deigo Perez Garcia
her father → Diego Perez (romero)
his father → Catalina Lucero de Zamora
his mother → María Petronila de Zamora
her mother → Maria de Zamora
her mother → Pedro de Zamora
her father → Catalina de Ocampo
his mother → Sebastián de Saavedra
her father → Isabel de Sanabria y Sotomayor
his mother → María de Sotomayor y Ruiz de Orellana
her mother → Beatriz de Vargas I y Orellana
her mother → Isabel Pizarro de Vargas
her mother → Gonzalo Pizarro Rodríguez de Aguilar, Capitán de los Tercios-Hidalgo
her father → Hernando Alonso Pizarro de Hinojosa, Regidor de Trujillo
his father → Teresa Martínez Hernández Pizarro de Carvajal
his mother → Sevilla López de Carvajal Bejarano, Señora de la Dehesa de Valero
her mother → Mencía González de Carvajal
her mother → Sevilla López de Villalobos
her mother → Fernán Rodríguez de Villalobos, Señor de Villalobos
her father → Teresa Sánchez de Castilla
his mother → Sancho IV el Bravo, rey de Castilla y León
her father → Alfonso X el Sabio, rey de Castilla y León
his father → Ferdinand "the Saint", king of Castile and León
his father → Eleanor of Castile, Queen consort of England
his daughter → Elizabeth of Rhuddlan, Countess of Hereford
her daughter → Margaret de Courtenay, Countess of Devon
her daughter → Sir Edward de Courtenay, of Godlington
her son → Sir Hugh Courtenay, MP
his son → Joan Carew
his daughter → John de Vere
her son → John de Vere, 15th Earl of Oxford
his son → Aubrey de Vere
his son → Lady Jane Hunt
his daughter → Captain John Hunt
her son → Eliza Anne Pegram
his daughter → George Pegram, III
her son → Elizabeth Ryves
his daughter → Timothy Rives
her son → Rebeckah Hicks
his daughter → Robert Hicks, of Sussex County
her son → Nathaniel Hicks, I
his son → Chief Charles Renatus Hicks

how is he Cherokee chief then if through white hicks family no offense

Nathan Hicks had children by a Cherokee woman so their children were Cherokee. You are distantly related to the Cherokee Hicks family, but only through their white line of descent.