Totally hear you, Cassius. Here's my method, though.
Here are the steps...basically...and of course I could be wrong but take it with a grain of salt.
1. We know Natasha Otomoski is equivalent to Satoshi Nakamoto. That's very obvious.
2. To obtain NATASHAOTOMOSKI=SATOSHINAKAMOTO we know how the letters have to be arranged. Its exactly what Watashi-Kokoto said (whether he's the OP or not doesn't matter).
3. So numbering 1-15, we get "5, 2, 3, 8, 13, 6, 15, 1, 4, 14, 7, 11, 10, 9, 12"
4. Now let's use an alphabet:
5. A=1, B=2, C=3 D=4, E=5, etc..
6. Now rearrange the alphabet using step 3:
7. "E B C H M F O A D N G K J I L"
8. This is the decryption key.
9. (8,2,3,9,1,6,11,4,14,13,12,15,5,10,7)⇔(5,2,3,8,13,6,15,1,4,14,7,11,10,9,12)-1
SUMMARY
What I'm saying is that we know the NATASHA --> SATOSHI is a permutation. So, why wouldn't the rest of the phrase be as well? I could be totally in left-field, for sure. But this is my best assumption.
My issue with this is that while it's clearly an anagram, it doesn't have to be a permutation cipher. In fact, the odds of it being a permutation cipher actually seem pretty low - because the key has to be 15 characters long. Example:
SATOSHINAKAMOTO
CRAIGSWRIGHTBTC
A key exists that maps the first to the second... but that doesn't prove anything.
3- or 5-character keys would also work, but none exist that map Natasha... -> Satoshi. If there was one, this would dramatically increase the odds of being on the right track.