Chaga is parasitic and grows exclusively on living trees.
The tree you have pictured appears to be rotting. Additionally, the mushrooms on that tree have a clear top and bottom. Although the coloration is similar, the picture above does not appear to be Chaga.
I will, however, do some research to see if I can find what fungus in fact is growing.
Hard to tell from photo, but: "gills" look yellow which is wrong for a button /agaricus compestri . Do they have gills ? If they have a spongy matter and not gills they are likely some boletin . Usually found under conifers. If so, likely edible but not much flavor.