I guess you can say this is a follow up to my previous thread on third party games on Nintendo consoles. But a common complaint about Nintendo systems was that the company only designed its hardware for its own first party developers, with no regards or care to what third parties think. It's easy to come to this conclusion given the struggles systems like the Nintendo 64 and Wii U had when it came to securing developers, and in some ways it is true.
Some of Nintendo's home consoles in the past came off as if they were primarily designed for Nintendo's own needs. More specifically, they seemed like they were designed for Shigeru Miyamoto's needs. Everything about the N64 for example was designed in a way to suit the whims of Miyamoto for what he wanted to do in games like Super Mario 64 and The Legend of Zelda: Ocarina of Time. The Nintendo GameCube's odd controller layout? That was all because Miyamoto wanted his games on the system to be played in a very specific way. The simple button layout of the Wii Remote? Miyamoto wanted to make console games more accessible to newbies.
These systems were designed in a way that that conformed to what Miyamoto wanted out of home console gaming, and while these platforms excelled at what Nintendo and Miyamoto aimed for, they struggled as general purpose gaming platforms, especially compared to Sony and Microsoft's consoles.
Nintendo often even kept its own developers in the dark about their hardware too. Super Mario producer, Yoshiaki Koizumi wasn't told about the full details of the Wii U until the moment it was revealed at E3.
But as I said in my previous thread on this topic, I don't think this should be a blanket statement that applies to all of Nintendo's consoles. Because if you look at its handhelds, there is a very different philosophy going on. While the Nintendo DS and Nintendo 3DS for example had significant input from Miyamoto, the development teams of those systems understood that they still needed to function as general purpose game systems for other developers as well. The DS may have had its touch screen, but the system still had a full controller layout for more conventional gaming.
And on the topic of Nintendo taking in third party input for their hardware. It's actually a lot more common than people think. The 3DS' circle pad pro accessory? That was created solely to appease Capcom and other third parties for things like the Monster Hunter franchise (also the main reason behind the New 3DS' creation). The Wii U GamePad going with clickable analog sticks was made at the request of third parties as well. Capcom even asked Nintendo to increase the RAM of the Nintendo Switch to 4GB so that they could run the RE Engine on it (to which their request was granted).
Speaking of the Switch, from the very beginning, Nintendo worked to take input from both its own EPD teams, and various third party developers as soon as development of the Switch began. The final Switch hardware was the result of this back and forth communication (How Capcom got their extra RAM). In fact, the Switch takes more from Nintendo's handhelds in regards to third party relations and hardware design based on that, than it does its home consoles.
So does Nintendo design their consoles for their own games? Yes and No. Their strength has historically been with how they've integrated their hardware and software with each-other, even with the Switch. But I don't think they're as insular to other developers' needs as people have sometimes painted them as. It depends entirely on the console in question.