Nether* plants are plants that are only found in the nether and are uncommon plants.
Breaking one will give 0-1 Nether* fruits.
Nether* fruits are harvested when you break a nether* plant and are supposed to be a small substitute for fire resistance potions. They also look like pomegranates but has flesh that looks like lava.
Effects when eaten:
Nether* Fruit ingestion: Like fire resistance except only has a maximum effect time of 15 seconds
When the sum of the Nether* Fruit ingestion and the additional 5 seconds of the Nether* fruit is 16 or more you will be set on fire instead and have both haste and Nether Fruit ingestion effect gone.**
They add 5 seconds of the Nether* fruit ingestion effect and has a cooldown of 2 seconds before it can be eaten again and restores 4 hunger and 2.1 saturation (Like chorus fruits)
Nether* flowers can only be placed on soul sand regardless of light level.
Nether* plants and flowers behave exactly the same as Chorus flowers and plants. They are also just re-skins of Chorus flowers and plants.
I just feel like adding this suggestion because most of the time it takes only like 10 minutes before all my potions of fire resistance are gone. Also I just want to add plants in the nether as well for some reason
So... Chorus plants, but in the Nether. No reason to add this, would be strange, and it's unoriginal as all hell. (See what I did there?) You literally said it: This is just a reskin and it has no reason to exist. And "rare" doesn't mean "balanced," anyway.
This idea is quite redundant with Chorus Plants, you even state yourself that these Nether plants are reskins off them. There's not really much use in them, 15 seconds of fire resistance wouldn't be useful in some cases, and with the add on Nausea or to, ironically, set the player on fire, to attempt to balance this suggestion dampens it as well.
Also, plants aren't exactly a fit for a Nether with a barren and cave-like environment, even if it's a mythical one. I suggest a more unique idea than just a plant, and to give it a little more of a unique aspect that makes it feel as if it's part of the Nether.