I found my issue.
There is nothing wrong with my Isaac Sim stage and ActionGraph.
The issue I had was that I didn’t set Fixed Frame properly in RViz.
Because I don’t know enough RViz, I set “base_scan” in the Target Frame property from Current View (where be default the value is Target Frame ). After setting “base_scan” in the Displays/Global Options/Fixed Frame (default value was “map”), I was able to see the laserscan and PointCloud2