Q
Is the character card from my opponent's battle zone, swapped out by NIRA-CHAN (Hippocampal Pain)
's effect, put in the power charger even without SEND TO POWER?
A
Yes. Whether or not the character card from your opponent's battle zone has SEND TO POWER, it's swapped with the card from the power charger.
After that, power is counted as usual by whether the cards in the power charger have SEND TO POWER.