ReignOfComputer

OT/Misc > Memories > Memories with: OT > Change Memory Type to Index 0 (first item).

OT/Misc > Memories > Memories with: OT Change Feeling drop-down until it works.

Legal

OT/Misc > Memories > Memories with: OT > Set Intensity to position 3 or greater.

Are you editing the Pokemon while it's in your party? Don't heal or go to something that might refresh its stats either.

Sounds like you're confusing ROM hacking with save editing. You can open up your save file in PKHeX to inject Nidoking.

Attach the .sav file.

It is a feature introduced in 20180319. A toggle has been added, and you'll see an option to toggle this behavior in the next release of PKHeX.

Can you verify if .NET Framework 4.6 is installed?

This was introduced on 31st Jan 2017. There hasn't been any changes to GetFrameworkVersion() (which is what your error stems from) since November of last year - may want to check if it's something on your computer's environment instead?

Doesn't exist.

Shift+DoubleClick on the Box Tab. Should bring up a window of boxes.

Thanks for reporting! Looks like Miror B's 2nd chances aren't populated in PKHeX's database: https://github.com/kwsch/PKHeX/blob/master/PKHeX.Core/Legality/Encounters/Data/Encounters3.cs#L447 Since Miror B can be encountered in more than one location, may need a special way of detecting this? Job for @Kaphotics

Hi, thanks for reporting. This is a known bug with the latest release and will be fixed in the next one.