Do Nintendo's games make up the majority of your library, or those from others?

I have to check, but I think Nintendo is the most dominant publisher in my library overall, but I definitely have more 3rd party in my collection.

Out of 77 games I currently have 19 are published by Nintendo. 9 are first party.

I checked. I have 8 first party games
And 11 third party games

The majority of Switch games I have are third party.

Switch is kind of different to past Nintendo systems in this regard-- where in the past if you buy a Nintendo system as your secondary you obviously just want the first party titles, so it wouldn't be strange if you only own ~12 whole games. With the Switch, even if it's your second system, lots of people will want to pick up Doom, Skyrim, Borderlands, Bioshock, Witcher 3 etc. just to have them on the go.

To answer the question, Third Party. But I obviously bought the Switch mostly for First Party titles.

I have mostly third party games.

That's exactly the games I have.

To answer the question, mostly 3rd parties, since the Switch is my main console.

I have about 40 games and maybe about 4 of them are Nintendo games (Super Mario Odyssey, Zelda, Mario Kart, Smash Bros)

In the moment I have 49 third party games and 20 first party games.

47 third party, 20 first party. However, some of those are hard to pin down like Dragon Quest 11 and Octopath Traveler. Nintendo published them and is listed as the publisher on the games overview screen on the Switch, so what are they? To me those are Square Enix games. The same applies for Snipperclips, Marvel Ultimate Alliance 3, Astral Chain and Daemon X Machina. And where does Mario x Rabbids belong to?

However, the majority is third party anyway.