You chart is missing that substituting Nature for a skill and Channeling nature are two separate decisions. Instead of flowcharts, maybe some actual examples might help. Examples from 2nd edition.
If you are acting within your Nature, you are never at risk of tax. So that should be pretty simple.
You can only be taxed if you are acting outside of your Nature or channeling your Nature when outside of your Nature descriptors.
Channeling Nature (Within)
Gerald the Halfling needs to sneak past a guardian golem (Scout test vs Guardian’s Protecting Nature 5).
Gerald
- Scout 2
- Nature 5 (Sneaking)
Since Gerald has a scout of 2, he cannot use his Sneaking Nature to substitute the skill ("Acting Within Nature rules).
He does have a persona point, so he spends it to Channel his Nature and muster more dice. He adds his current Nature of 5 to the dice pool.
He rolls 7D (scout 2 + nature 5 vs Guard’s 5D)
Gerald fails by a MoF 2. Because he acted within his Nature, there is no tax. As a twist, the guard spots him and sounds the alarm. More troops are on the way now!
Acting Within Nature (Doubling)
Bjorn the Bjorning wants to sail home out of the fjord to the party’s island camp during a severe storm. That’s a tough Sailor test Ob 4 (factors: small boat, known (1), summer, storm (3).
Bjorn
- No sailor skill
- Nature 4 (Sailing)
Instead of using Beginner’s Luck, he uses his sailing Nature to substitute for the sailing skill. This is Acting Within his Nature. His clan has been living on the sea his entire life, and he is quite comfortable sailing after all. But, he doesn’t like the odds of rolling Nature 4D on Ob 4.
He does have a persona point, so he spends it to Channel his Nature to muster more dice. He is doubling his nature by using it and channeling it.
He rolls 8D, but fails by a MoF of 1. He is not taxed because he is still within his sailing nature. His Nature is still 4. As a twist, the storm floods the boat, and now they have to bail out the water or abandon ship.
Acting Outside of Nature
Simit the Skyrnir Magician rushes to knock a lone goblin out with his staff. Simit does not have the fighter skill nor any Nature descriptor to apply to this fighter versus test (Goblin Nature 3).
Simit
- No Fighter skill
- Nature 6
With a health of 3, beginner’s luck would give him 2D, so that is not a good choice. But his Nature is 6 though. He can substitute his Nature for the fighter skill, but because he is outside of his Nature descriptors, he may be taxed by MoF. So there is some risk, but his Nature is full, and he can absorb some loss.
Now, if he wanted to spend a persona and channel Nature he has to at least pay a tax of 1—no getting around that, and anything beyond that he also has to pay if he fails.
He fails by a MoF of 2 and his current Nature goes down from 6 to 4.
Hope this helps.
