What I want to know is what year the codename for the successor is leaked.

Project Cafe was Wii U.
NX was Switch.

I just want to know it's codename!

I really thought March 2023 for a while. Now I'm thinking March 2024. We're in a once in a century level pandemic that has caused supply chain mass shortages.
November 2023 could happen, but that's the earliest I see right now.

I've been saying Holiday 2024 and I stand by that for now. I'm not too keen on March releases because that pretty much means that it would hurt their holiday sales for the prior year (ex: if it releases in March 2024, it would likely be announced before Holiday 2023 and hurt sales that holiday). Worked for the Switch because the Wii U was dead and 3DS was limping along (also the Switch was not backwards compatible with the 3DS whereas the Switch 2 would hopefully be backwards compatible with Switch).

Also, they have a strong lineup this year, which means that the dev teams releasing games on Switch this year won't have stuff ready for Switch 2 probably until 2025 at the earliest (we could at least see Mario Kart in 2024 and then get games like Animal Crossing in 2025, Pokemon & Mario in 2026, Zelda in 2027, etc.).

I think sales this year will greatly impact this decision. Call me crazy, but I honestly see 2022 as a possible increase in sales from 2021. 2020 was an odd year, that makes 2021 look like a decline, but I think sales are still moving in a positive direction. if 2023 proves to be close to 25m. I don't think there is any reason for Nintendo to Announce a new console. 

Nintendo did make that mistake with the DS and it ended up really hurting sales, at the time they made the mistake because they thought the 3D gimmick would be a super hit. I am not sure if Nintendo is seeing something similar with a new console. I personally chose 2026 as the release of the new console (march 2026). The way I see it, or hope is that sales could go like this:

2022: 24M

2023: 22M

2024: 18M

2025: 12M

2026: 8M

2027+:5M

Total Sales: ~190M

I know this "prediction" can easily blow up in my face, but I see the Switch selling really well and Nintendo could just ride this wave a little longer to release something very special in a few years. 

Late 2022 / early 2023. Dev kits are already out.

I have been saying 2025 pretty much the entire time the Nintendo Switch has been out.

They said they would be going beyond the normal lifecycle on many occasions.
And the software to support that has to be lined up in advance.

Obviously there have been many delayed games, and hardware production nowadays being more constrained could push it further than that, but still too many variables to account for.

How will everything line up for launch games for first party and third party? Will chip shortages still be ongoing? What features will Nintendo try to add to the new hardware? Will that need more time for the tech to be ready for launch at a mass market price? etc., etc.

I imagine it will be like DS to 3DS, in that, it will be iterative, backwards compatible, and have some new features, but nothing that breaks the appeal to a large degree (a la Wii U).

I do wonder how inflation could effect things as well, it might stifle the console a bit if it has to push a higher price tag.
And then does Nintendo shift strategy (or marketing, or even software) a bit to try and justify that higher price???

So many variables, but I still think 2025 is the most likely year right now.

To be announced between 2023 to 2024.

I think around 2024.

I think it’ll come out when the launch software is ready for it. I also think Nintendo will unveil it 4-8 months before release. I doubt they’re going to string everyone along with a “blah blah NX” lead up and instead we’ll get some reveal package like the Switch’s, and then a more thorough event about a month before launch. Again with people moaning like they did with the Switch being announced for release shortly after the unveiling: “IT’S TOO SOON! NINTENDO CAN’T LAUNCH A CONSOLE WITH SUCH LITTLE TIME AFTER UNVEILING IT! IT WILL BE AT LEAST HOLIDAYS 2017 OR MUUUCH MORE LIKELY, HOLIDAYS 2018!”

It's probably Dolphin 2