My 14 Year Old Niece Gets EVERYTHING She Wants?

And i mean EVERYTHING. Last year she got new (expensive) clothes, expensive watch new iPhone7 ect ect. This year she's getting like $1000 worth of new clothes by big brands like calvin Klein, Nike, Adidas and other brands like that, even new shoes that cost like $300, make-up brands like Mac. Everything she asks for she gets. Her mum, had to start working because she doesn't have enough money for her daughters tastes. And she drives her everywhere. My niece does work, but doesn't ever buy her mom a good gift.
I don't know why my sister is doing all of this for her. Like i'd be fine with it, if her daughter was grateful. But if she doesn't get what she wants, she gets moody and gives everyone dirty looks.
As for my nephew, he doesn't get nearly as much spent on him and he NEVER complains. He's grateful for everything he gets.
Do you think this is okay? Am i like the only person who thinks she a little spoiled?

Added (1). okay, so there are a lot of people telling me to mind my own business. Yes i understand that, and i do. But i HATE the way my niece treats my sister she has no respect for her mother at all. It pisses me off. And me and my sister are very close, so it is my business.
and my nephew gets jealous, and you can see that pretty clearly. I never thought id get this much attention on this.
i was just asking if anyone else has someone treated like this as well, i think its unfair

Spolit little 14 year old brat!

It's clear you just need to get over it. There's nothing you can do. The only suggestion I have is to be a good example to her. Show her by your actions what it means to be grateful and to serve others.

Its the parents fault.
nothing you can do about it

Spoiled maybe, Parents sometime raise their kids based on how they were raised. Say, a child grows up hungry, all his \ her kids are fat, not always but more true than not. Grow up Fatherless, the kids live in the house till their 40.
Poor, kids have everything. It's our demons that drive us.

Not your circus, not your monkeys… Let it go.

You don't have a daughther… The first daughter is always spoiled. Its just the way we're made

Maybe she's afraid of her and spoils her so she don't get mean

Of course she's spoiled and she'll grow up into a miserable adult. I have no idea why your sister thinks this is good parenting, but it does produce unhappy adults because they feel so entitled to everything. They spend the rest of their lives looking for someone to cater to them.

But there's nothing you can do, other than try to be as kind and supportive of your nephew as you can. He may not be showing it but he's aware of the disparity. When he's a teen, odds are high he'll starting acting out in a big way if he doesn't have someone in his corner. You could make up for a lot by letting him know how special you think he is!

So? She's a spoiled little brat who is in for a rude awakening wen she moves out. Since she's not your kid there's nothing you can do

A) not your problem

b) she'll suffer for it later

c) he'll be happy as long as he doesn't get sucked into supporting her. This actually happened to my nice friend, he helps support his sister even though she's a lawyer!