Someone with the National Battlefield Park will know where Confederate dead were buried. For two days afterwards much of the Confederate army remained in the area, collecting arms and equipment and burying the dead. I don't believe any marked CSA graves exist there, but call and check. This man was probably buried on the same site where he died, and it's not hard to trace the path of each brigade. The battlefield park office has detailed maps available which show the location of each marker. Using the map and a detailed description of the battle, such as Cozzens' book on Chickamauga, you ought to be able to locate probable sites.