This would make "Satoshi Nakamoto" a criminal for not declaring the genesis block on his taxes.
I am thinking: BTC=0 value when satoshi generated them. Now they are worth billions. There is capital gains, but assume he renounced his us citizenship before converting them to fiat. What would happen?
His best option would probably be to create an irrevocable trust which pays him a percentage every quarter. Then he won't owe any taxes on what has already accrued.
Then he can consider expatriation or moving to Puerto Rico.