You do realize Nyx is immortal, right?

Not just Nyx. All allicorns are immortal. However, that just means that they can't die of old age. That doesn't mean that they can't die by other means.

There is only one way to kill an allicorn, and that is to deprive it of the magic it needs to heal. Any wounds they sustain would be healed in moments otherwise. This goes double for an ex-queen.

True. Good thing that didn't happen. Argument, now invalid.

While I the topic of Nyx, I don't understand why everyone hates her so much.

Sure, when she was Nightmare Moon and she was constantly pitying herself to the point where I wanted to slap her.

Besides that instance she's essentially Fluttershy. At least that's what I thought.

Having been in a similar situation (Hating yourself, not being a dark queen) I think she handled it well. I'm not sure why the hate either. Some say it's because she's an OC pony. So are most of the background characters the grow to love. They don't even have Lyra's name right anymore. "Heart strings" or whatever. I liked Nyx, and I especially liked the fanfic. Let people hate, but I'll still defend her.

Same here. I'll defend Nyx. She may be an OC pony, but she's adorable as fuck.

Also, on the whole Lyra/Heartstrings thing, other background ponies are getting names. Carrot Top is now Golden Harvest and Derpy, while her behavior is canon, has been given the name Ditzy Doo. Although, there has been speculation on the fact the Ditzy Doo and Derpy are actually two completely different ponies. There is another theory that they're the same pony, but, similar to Launch from Dragonball, she changes back and forth under certain circumstances. That's the idea I'm going with at least.