Is Chaturanga/Shatranj an early form of chess or is this altogether different? I had heard from someone that Chess evolved from Chaturanga then Shatranj.  Are there any pointers towards this?

I would like to know counter arguments as well, if any.
Those two games are indeed early forms of chess. The pieces were similar, although their moves were different, and there were some chess rules that had not yet been invented; however, chess evolved from those early games.