No, it is highly unlikely that the Earth's inner core could be made out of a black hole.
A black hole is formed when a massive star collapses under its own gravity, creating a region of spacetime with a gravitational pull so strong that nothing, not even light, can escape from it. Black holes are characterized by their event horizon, which is the boundary beyond which nothing can escape their gravitational pull.
The Earth's core, on the other hand, is primarily composed of solid iron and nickel. The inner core is believed to be a solid sphere, while the outer core is in a molten state. These layers are formed due to the Earth's internal heat and pressure generated by various geological processes.
Black holes are typically formed from the remnants of massive stars and exist in the vast expanse of space, not within the interior of planets like Earth. The conditions required for the formation and maintenance of a black hole are vastly different from those found within the Earth.
Therefore, based on our current understanding of black holes and the composition of the Earth's core, it is highly improbable that the Earth's inner core could be made out of a black hole.