Change custom drop with different harvest tool level (need HELP)

Hello there :D

I started a few days ago with a new mod. I'm currently adding a few new ores. with the "Copper" Ore (Ingot based) I faced a problem. What I want:

CopperOre should drop itself if destroyed by harvest tool level 2+ (iron pickaxe or better) --> this one works fine

But I want also that:

CopperOre should drop CopperNugget (1x-3x [random amount]) if destroyed by harvest tool level 1 (stone pickaxe)

I think adding the copper ore twice doesn't work because it would spawn twice as much and I could destroy half of the blocks with the stonepickaxe and half of the blocks with ironpickaxe only.

Thank you for your help, I don't know how to add this by feature or by coding. If I have to Code it, please tell me what and where in the console.

Have a nice day :D