Nuclear energy is energy stored up by the strong force, while electrical energy is stored up by the electromagnetic force.

Aside from that, there is no meaningful relationship. It is possible to build a machine that can convert one into the other, though.

Nuclear Energy Vs. Fossil Fuel. Nuclear energy is the energy stored in the nucleus (core) of an atom. The energy released can be used to generate electricity. Fossil fuels—which mainly include coal, oil and natural gas—provide the majority of energy needs around the globe. Jan 9, 2018
Nuclear Energy Vs Fossil Fuel

Fossil fuels can also be used to make electricity. Water power - dams - are also used to make electricity. Nuclear energy involves lots of radiation at the nuclear power plants, but it doesn't have the types of pollution that come from burning oil and gas.