The nuclear reactions result in mass loss (or mass defect) that transforms into energy according to formula: E = mc2 , wher c is the light
Nuclear reactions convert very small amounts of matter into significant amounts of energy.
Light is electromagnetic energy. Nuclear energy is energy derived from nuclear reactions, and the nuclear reactions could be either fusion or fission reactions. As regards the energy that appears from nuclear reactions, it can take different forms, including the form of electromagnetic energy.
Nuclear energy is not produced by chemical reactions
Nuclear reactions in the cores of stars convert hydrogen to helium
Fusion and fission nuclear reactions.
No. Nor can you convert mass into energy. In any reaction - including nuclear reactions - both the amount of mass and the amount of energy remain the same, before and after the reaction. For example, the energy that escapes from a nuclear reaction also has a corresponding mass. On the other hand, the energy existed before the reaction as well, in the form of (nuclear) potential energy.
Nuclear energy is obtained through fission and fusion reactions.
Energy (in the form of heat), also free neutrons.Binding energy
energy
The light dependent reactions take in the light energy and convert that to chemical energy, but it is in the Calvin cycle (light independent reactions) where the chemical energy is stored in a complex sugar.
Nuclear fusion
I don't know of any way to do this. Nuclear energy simply provides heat, so could conceivably be used to drive chemical reactions, but I don't think this has ever been done.