well - less see, since it is 474 million times further away then the sun, the in-nava-lation from a putative 50 billion sunpowers would be approx 2.2 * 10^-7%.

Pluto recieves about 7*10^-4 the amount earth gets from our sun. So that mean Pluto gets about 3000 times the amount of energy from our sun as Earth would get from the nova.

Or the nova will effect us about as much as the sun would effect a planet 54 times further away then pluto.