What i know:
100% chance of occurring
Not an nvidium problem
the game once worked, before i changed quality preset for Distant Horizons (alpha build for this iris version) to one of the presets but not "custom" which shipped with the mod when downloaded for the first time.
My game booted up after removing this version of iris (100% chance of this in fact, being an iris problem)
The Minecraft crash report:
The game crashed whilst initializing game
Error: java.lang.NoSuchMethodError: 'void net.coderbot.iris.shaderpack.ProgramSource.<init>(java.lang.String, java.lang.String, java.lang.String, java.lang.String, net.coderbot.iris.shaderpack.ProgramSet, net.coderbot.iris.shaderpack.ShaderProperties, net.coderbot.iris.gl.blending.BlendModeOverride)'