で、森コビちゃんの話に戻りますけど、『森コビちゃん』の名前は森を散歩している時に思い浮かんだのですわ。
To get back to talking about Morikobi-chan, I thought up her nickname while we were walking in the woods.

「あなた、森の小人さんみたいだわ」
"You're like little people of woods."

とアタクシ、森コビちゃんに言いましたの。
I said to her like that.

小柄な体で森の小径をてくてくと歩いている彼女を見ると、まるでかわいい森の小人さんそのものでしたもの。
Because she looked like as if she was just like little people when I saw her small figure walking along the paths in the woods.

「ええ? 森の小人?」
"What? Am I little people?"

と森コビちゃんは言いましたけど、まんざらでもない様子でしたわ。 
said Morikobi-chan, but she wasn't altogether displeasing.

それで『森の小人さん』=『森コビちゃん』になったのですわ。
And so, "Mori-no-kobito-san"(Little people) = "Morikobi-chan".