She's widely referred to as "Liz", especially by her political opponents. "Liz" is short for "Elizabeth" the way "Ted" is short for "Theodore".

I don't even understand calling people you don't know personally by nicknames.

"I like Ike"

It's been common in politics for a century, even among supporters.

Odd. How do you refer to the current Senate Minority Leader? Or the President? Or the 42nd US President? Or the 39th?

He calls himself Mitch though. This is an unapproved nickname.

Yeah, like all those cads who say "Joe Biden" instead of "Joseph Robinette Biden, Jr.". Who do they think they are?

Can you show me an example where she refers to herself as "Liz"? I can show you a ton where Joe Biden refers to himself as "Joe".

Her own supporters seem prone to chants like “Run, Liz, run” ('for president', I assume, not 'away'). So I think the nickname is fair game for everyone else unless she explicitly disapproves.

Agreed, at first I thought this was referring to someone else.

Funny you ask. I have no idea where I heard but I thought it is easier to type than the whole word. If you google Liz Warren, it auto completes to Elizabeth Warren so its def. a thing.

Thanksgiving maybe?

Massachusetts?