Minecraft – Custom predicates for custom items in Minecraft don’t work

I have created a custom resource pack and model using Blockbench, now I want to have a custom texture for a gold nugget with certain custommodeldata but when I enable the resource pack and load in game, it doesn't show. It is still a gold nugget.

Contents of my folder: (im on version 1.15.2)

pack

• pack.mcmeta:

{
    "pack": {
        "pack_format": 5,
        "description": "Test pack"
    }
}

• assets:
  • minecraft:
    • models:
      • customstick.json:

{
    "credit": "Made with Blockbench",
    "texture_size": [32, 32],
    "textures": {
        "0": "custom/sticknugget",
        "particle": "custom/sticknugget"
    },
    "elements": [
        {
            "from": [7, 0, 0],
            "to": [9, 1, 16],
            "rotation": {"angle": 0, "axis": "y", "origin": [16, 8, 8]},
            "faces": {
                "north": {"uv": [0, 0, 1, 0.5], "texture": "#0"},
                "east": {"uv": [0, 0, 0.9995, 8], "texture": "#0"},
                "south": {"uv": [0, 0, 1, 0.5], "texture": "#0"},
                "west": {"uv": [0, 0, 0.999, 8], "texture": "#0"},
                "up": {"uv": [0, 0, 1, 8], "texture": "#0"},
                "down": {"uv": [0, 0, 1, 8], "texture": "#0"}
            }
        }
    ],
    "display": {
        "thirdperson_righthand": {
            "rotation": [100, 0, 90],
            "translation": [-7, 4.75, 2.5]
        },
        "firstperson_righthand": {
            "translation": [0, 8.5, 0]
        },
        "firstperson_lefthand": {
            "translation": [0, 8, 0]
        }
    }
}

    - gold_nugget.json:

{
 "parent": "item/handheld",
 "textures": {
  "layer0": "item/gold_nugget"
 },

 "overrides": [
  {"predicate": {"custom_model_data": 888765}, "model": "item/model"}
  {"predicate": {"custom_model_data": 5555}, "model": "item/customstick"}
 ]
}

And then in assets/minecraft/textures/custom I have a customstick.png texture file. Where exactly is the problem? This is the command I'm using for getting the item:
/give @p gold_nugget{CustomModelData:5555,customitem:1b} 1

I also have made textures/entity/creeper and it works in game, why doesn't this work? I followed an online guide for this