"Easily double" lol

But it would be a port, which would obviously not even showcase the NX's power. 

NSMBU helped push Wii U sales the first year of the Wii U's life, and it's first year sales were actually pretty good. Add to it the fact that NSMBU and NSLuigiU combined far outsold any LoZ and port (or remake) with the exception of Ocarina Of Time (best selling of the franchise again since the 3ds entry) it should paint a pretty clear picture. It we are going by financial success, LoZ is not the best route they could take (looking at numbers).

Very High
What better way to get back a hardcore audience into the Nintendo bandwagon than a New Zelda game as a launch title.

We don't know what NX is yet or what its power will be.  It's quite possible that it will be a somewhat modest upgrade over WiiU on the power side of things, depending on what it is.  And if that's the case, it would follow the pattern of Twilight Princess even further, which, ironically, is the one Zelda you forgot; TP's Wii sales alone are still a bit ahead of both NSMBU and NSLU combined.

However, the main point here is that you're not talking about a brand new NX Mario game launching with the system.  Then there would be means for discussion as Mario is the bigger selling series.  But a four year old port of WiiU's launch Mario, launching the NX?  As opposed to a brand new, never released Zelda as a draw for new hardware?  Remember, I'm assuming (possibly incorrectly) that Zelda is making its market debut the same day as NX, ala Twilight Princess.

20-30%

The only better way would be to launch with Zelda and the Star Fox that we all want - not the crappy one they are making for the Wii U, then release an F-Zero game 3 months later and nuke the core audience with a glorious Metroid Prime 4 half a year after the launch. Sprinkle that with some more casual games that are cheaper and easy to develop, give us a Mario Kart for the first Christmas, SMG3 some time after, Smash the next Christmas and you have yourself a console that core audience buys into.

Oh, and get all 3rd party games on board in 1080p/60fps - something nobody else can get. Now you're playing with power - again.

They'd have to skip a generation to have such a lineup saddly :(

I would put money on it.

You are correct. I don't know why but I thought They outsold TP by a little bit. Either way, as close as the numbers are, and one being on the best selling Nintendo home console and one being on the worst selling Nintendo home console should also be taken into account. 

And I'm not talking about nmaking a port of a 4-5 year old game (when NX launches) I'm just saying financially speaking they could make another NSMBU for a fraction of the cost, and hystorically speaking make more of a profit. That would be the best way to go if we are just going by the profit margin.

If they release a home console in 2016, they will be skipping a generation Let's face it, Zelda is pretty much done for Christmas 2016. All they have to do is change the Star Fox they are developing into a game with good graphics and multiplayer. I think if they properly invest in this franchize, it can become big like Splatoon did. F-Zero isn't the type of game that should take years to develop. Retro should be working on MP4 for some time already. I mean, Nintendo isn't developing anything big since Splatoon. They have a full year now and the next year to get ready for the launch window, that lasts around 6 months. That's a lot of time to make games like F-Zero or turn Star Fox into a great game. Mario Kart can just be un upgrade of MK8. SMG3 - should be in development already. So yeah, I think they have enough time to make these games.

Still, the kicker is the best performance of 3rd party games. I really want that.