Nell could be short for....

[FriggFRIGG]

Any ideas?
I don't mind if the connection is a little tenuous...

Helen, Helena, Eleanor, Ellen.

Traditionally, it's Helen, but it could be Eleanor. I can't think of others off the top of my head, but I'm sure there are some.

Penelope

Bloomin'Nell

Sorry, not useful.

Prunella?

I knew someone at school called Chanelle who was Nell/Nellie for short.

Eleanor
Helen
Helena
Nelly
Fenella
Cornelia

I love Nell.

Eleanor
Helen
Ellen

ooh, yes i like Ham's ideas.

anything with -nell- inside.

Elizabeth.

The connection is quite tenuous, but Nell is short for Eleanor/Helen based on 'mine Eleanor', so also works for 'mine Elizabeth' or any name starting with 'El' really.

That's very interesting Outraged...

You know, Outraged, I wanted to say Elizabeth too , but thought it was far too tenuous!

Fenella is my favourite so far...

That is interesting. It makes me wonder though why there's no such name as Rell. In Liverpool, we all say "Our 'Elen" or "Our Elizabeth"

And Nella...

Eleanora

Nutella (kidding)

Round here it's generally short for Fenella.

Petronella

Noelle

Manuela

Quenelle

Antonella

I always associate with Elizabeth too, never Helen

Eleanor and Helen emphasise the first syllable. Mine HEL-en, mine ELL-ea-nor.

With Elizabeth the emphasis is on the second syllable, so I don't think the "mine" thing works as you wouldn't say "mine ELL-izabeth".