minecraft-assets/data/minecraft/worldgen/configured_feature/nether_sprouts.json

{
  "type": "minecraft:nether_forest_vegetation",
  "config": {
    "spread_height": 4,
    "spread_width": 8,
    "state_provider": {
      "type": "minecraft:simple_state_provider",
      "state": {
        "Name": "minecraft:nether_sprouts"
      }
    }
  }
}