Is there any resource on how to retexture chisel blocks (primarily Marble, as I would like to re-implement the old raw marble and regular marble bricks textures)?

Thank you

https://github.com/Chisel-Team/ConnectedTexturesMod/wiki

Otherwise, it works the same as any other mod/resourcepack.

Yes, again, same as you would with vanilla or any other mod. You can find the base mod assets in this repo.