Re: WDYT of nicknames, and help choosing a nickname...
In general I think it's best to let a nickname come naturally, or not, as the case may be. If you do pick one, you should be prepared for it to be cast aside later on, and not get attached to it; it's not your name to be called by, after all.
Din-Din is awful; it's like a cutesy-poo way of saying dinner: "Din din, Morris!" like in the cat-food commercials, or like in the movie Whatever Happened to Baby Jane, where "din din" turned out to be a dead bird.
Nadz is definitely out also, because it sounds just like gonads.
If it was me, I'd use nina or Dina. Some might like Nay-Nay.
Don't like Nin because it reminds me of ninny.
I think, therefore I judge.