The Superhero Database Classification number, or SHDB Class, is a number that represents the overall 'power' of a character. All traits of a character are used for calculating the Classification.
What it DOESN'T mean
This doesn't mean that a higher class would always beat a lower class character. But the bigger the difference in Class is, the more obvious it is who'll win in a fight.
How is this calculated
( INT^1.3 + (STR*0.5 )^2 + (SPE*0.5)^2 + DUR^1.6 + (POW + (SPS*SPL))^2 + COM^1.8 ) ^ TIER
Super Power Score and Level
Every Super Power has a score (SPS) that is used to calculate the Class. Each Super Power also has 3 levels (SPL). The level is set when connecting that Super Power to a character. The level determines the final score, of the Super Power, being used in the calculation.
The Night King has magic powers and can survive fire, as shown in the episode “The Long Night” when he walked through Drogon’s flames unharmed. However, it is not clear if he can resist an atomic breath, which is much hotter and more powerful than regular fire. Also, dragonglass and Valyrian steel are not the only things that can kill him, as Arya proved when she stabbed him with a dagger made of catspaw, a rare metal that has similar properties to Valyrian steel...
So I think Godzilla has a better chance of winning!