Taking a Tesla Coil to generate artificial lightning sending the bolts down a tube lined with magnets that creates a solid beam of energy that is sent out into the vacuum of space at the speed of light. Tesla coil would be powered by a nuclear engine and argon gas would be inside of the magnet chamber, Not sure how to design the exhaust that allows the lightning energy to be expelled hopefully creating thrust.

So what is your question?

There seems to be a misunderstanding of what "lightning" is. It's a stream of current, not light (nor a "solid beam of energy"). So it cannot move at the speed of light. And the electrons must flow from something to something - not just whiz off into space.