We investigate the internal dynamics of a related model system, consisting of a K@C⁺₆₀ endohedral complex enclosed in a C₄₈₀ nanocapsule. We show this to be a tunable two-level system, where transitions between the two states can be induced by applying an electric field between the C₄₈₀ end caps, and discuss its potential application as a nonvolatile memory element.