Not nicknames, but I usually call them by their first names out of a habit that just stuck, lol.

Lol... I got my head knocked off for using anything other than "Mum" and "Dad"...

Maw n paw..
in a Waltons accent

There was a group of situations where I referred to my dad by the name Stormy.

Yes. Both of them start with........"The Late........."

Mami & papi

Yoda.

I just call them some variants of mother and father in my language, I don't use their names except for when I joke around. I love the nickname my dad has for my mom though, it's unique and very cute.

I refer to my dad as “sperm donor” 🤷🏻‍♀️ Does that count?

"Sir" and "Ma'am" seemed to work for them. 🤷‍♀️

Nope their names Sufficeth.

My dad's nickname is Paps

My mom, we got a spin off her real name

Nothing we hardly talk

Dead and Deader. Been gone awhile.

My dad was truly a horrible man. As a kid I used to have what we called waking nightmares a dozen times maybe throughout my childhood. In one of them the guy turned into a monster on me in my mind and terrified me while I was hallucinating. So that fit. Monster. He truly was one..

Mom, dad?

My mom is just Mom. My dad has a tendency to stand in choke points (places where only one person can pass through because of a narrow doorway or furniture arrangement). I call him "Man Who Stands In Choke Points".

Stan the man