I thought these were very common words, but from a recent conversation it seems they are not all as common as I thought.
- nibby
- nibnose
- nosey
Poll to follow.
If you know the words, do you consider them completely interchangeable?
‘Nosey’ as in (I assume) someone who’s always got their nose in someone else’s business, I’m familiar with. Nibby and nibnose, I’ve never heard before. Could it be regional?
“Nibby” and “nibnose” are clearly made up words. 
It could be. But if you’re in WV and I’m in SE Ohio, I just don’t know! 
Sorry, I never heard of nibby or nibnose.
I see from the urban dictionary:
And from further googling that *nibnose *or nib nose is related.
Nosey is a very common word to me, but I don’t recall ever seeing or hearing the other two before.
In this column (scroll down to “None of your beeswax”) this person says it’s a Pittsburghism. I know this area shares a lot of odd dialect features with Pittsburgh, so this might just be another one of them. 
If “nosey” is the same as “nosy,” as norinew says, I know that one. Otherwise, no.
Do they involve Sir Nose D’Void of Funk?
“Nosey” (although I would spell it “nosy” is quite familiar. My wife very occasionally uses “nibby”. From her usage, I thought it meant picky, but maybe not. Her mother grew up in Louisville and she has a couple other words from Kentucky.
I’m familiar with all three, plus the synonym “nibshit.” Grew up in Indiana, so I suspect they’re pretty regional words.
Really? You hear “nibnose” and “nibby” on a regular basis from non-family members?
I grew up in the New York City area, and now live in the outer reaches of Chicagoland. I know “nosey.” Never even heard of the others until this thread.
Pittsburgher here.
Here, we say “nebby”, which is probably cognate.
I grew up in western Pennsylvania, about 60 miles from Pittsburgh. I’ve heard all three (actually “nibbynose” instead of “nibnose”) growing up. I recognized all of them immediately.
Born and raised in the South. We have nosy people here, never heard of the other two.
Is “nosey” an alternate spelling of “nosy?” If not, I don’t know what it means.
“Nibby” and “nibnose” sounds like something a character on “iCarly” might say.
By the way, can I tell you how cute it is when you and Asimovian turn to the boards to settle minor quibbles between you? Because it’s totally adorable.
I know the word “nosey” from the Nosey Bears (TM, etc) toys from my childhood. If it’s related to the word “nosy” then that would be the only word I recognize on that list.
I also thought ‘nibnose’ meant something meaner than ‘nosey’.