Ray already is a nickname, but you could call him Ray-Ray.
Famous people named Ray:
Actors Ray Romano, Ray Liotta, and Ray Milland; musicians Ray Charles, Ray Toro, and Stevie Ray Vaughn; author Ray Bradbury; football players Ray Lewis, Ray Edwards, and Ray Rice.
The world knows him as the scarecrow from The Wizard of Oz, but the actor's real name was Ray Bolger.
100+ Bite-Sized One Syllable Middle Names For Your Cool Baby Boy, Boy Names That End In “Y”, Tiny Three-Letter Boy Names, Radiant R Names For Baby Boys, Simple One-Syllable Boy Names, Yee-Haw! Boy Names That Are A Little Bit Country, Wonderful Word Names Straight From The Dictionary, Boy Names People Won’t Shorten, Short, Sweet Baby Boy Names,