I don't agree with "let nature take care of it" in most cases. That amounts to leaving firewood to rot, and a bunch of weight that will come down when it feels like it, not when you plan for it. So, why leave a hazardous accident waiting to happen on property you or others use, walk or travel through? A lot of variables come into play with that, I understand, but it is another thing to consider.
If the pictured tree is well seated in the fork against the standing tree, there is probably pressure being applied (by the standing tree) through the length of the log down into the stump. If I had to guess, I would say the pressure is greater along the top surface of the leaner log than the bottom.
If you decide to cut it, the standing tree and gravity will push the leaner toward the stump, and the stump will probably try to right itself, so you have forces in multiple directions to deal with. If the leaner log is running straight without a bow in it, it will likely not move/sweep to the left or right very much when cut from the stump, but that is another direction of force to watch for by reading the saw kerf and any rips or cracks that appear on the bark near the cut.
Working with chainsaws in the woods is always dangerous. If you don't feel comfortable, leave it. I've found that some of the tension in freshly fallen or felled trees and limbs will self-release given time to relax. In this case with the stump, that probably won't happen; the only thing that can give much is the tree that it is hung up in. That tree will eventually respond to the pressure of the leaner, but it will take a while.