In Godbound, hit points are often used where other games would use hit dice. Is the gift "Intrinsic Health" supposed to add 2 extra hit points per level or hit dice if you're using a hit dice system like D&D?
It grants additional Hit Points to Godbound.
The idea to remember is that Godbound and other such tough people use Hit Points to give them more health, while nearly every one else has health equal to their Hit Die rating.
So basically Godbound uses both Hit Points and Hit Dice.
If an NPC that had HD instead of levels gained the Intrinsic Health gift somehow, it would likely add +2 HP per HD (because their progression uses HD instead of levels). Against most enemies, the NPC would get a bunch of HP that matter to their survival. Against Godbound enemies, this wouldn't help the NPC at all; Godbound damage HD directly and ignore those foes HP (including the bonus that might be granted by Intrinsic Health).
For instance, a Great Wyrm Red Dragon might have like 27 HD, and each HD is 1d12+3 HP, they might have 211 HP. Intrinsic Health might boost that to 265, which helps that dragon survive lots of stuff. But a Godbound can still kill it with 27 damage either way, because it has only 27 HD and bonus HP don't count.
NPCs don't use hit points, so technically it'd mean nothing. If you want to make an NPC tougher without increasing their hit bonus/saves/etc, just give them X extra hit dice that don't count for any other purpose than soaking up damage.
My rule of thumb is here; 1 HD in Godbound is equal to 10 HP in other games, like D&D, round as you like.
Example: If a beast has in D&D HD: 7d10+21, it becomes in Godbound HD: 9 (7+2).