According to several sources for Eurogamer, the Nintendo NX will be a portable handheld console with detachable controllers.
The NX will function as its own handheld console with its own display, but is reported the screen would be would have two controller sections on either side which can be attached and detached.
You will also be able to hook it up to a TV when you are home.
The site also said that a base unit is used to connect to the brain of the NX located within the controller to display to your TV.
Finally, it’s been reported that the NX will be using an Nvidia Tegra mobile processor and will be using its own operating system.