Generally, there would be no specific need for your additional 61-key controller to have midi-in, unless you wanted to daisy chain yet another keyboard through it, or if you needed midi to program midi channel number. etc. If you can set up the midi channel configuration of the new controller on the controller itself, then midi-out only should be fine, and if there's no midi-in that's a clear indication that you don't need it to program the controller.
It doesn't look like the Nord has a midi-thru function (for daisy chaining, but the manual may just be unclear), and if you're using midi-in on the Nord to access sounds or send patches to the Nord, it wouldn't necessarily be available anyway.
Yes, just plug that additional controller into your Uno and into the computer.