Why a submarine cannot simply power an aircraft carrier

Could a nuclear submarine dock with an aircraft carrier and supply its power?

No practical connection could tolerate the very different motions of the two hulls in a seaway.

A nuclear submarine and a surface carrier move through waves in very different ways. Any rigid mechanical or electrical connection between them would be loaded by those unequal motions and would be vulnerable to rapid damage. A submarine's pressure hull and sail are not designed to serve as a flexible power-coupling structure for a much larger surface ship. The arrangement is therefore mechanically implausible even before questions of efficiency and operations arise.