Nanokontrol is a USB device that requires a USB host, and the Juno DS does not function as a USB host. You have some other possibilities...
... connect both the Juno DS and the NanoKontrol to a host (typically your computer or tablet), and integrate them that way
or
... add a standalone host device that will essentially add 5-pin MIDI connectors to the NanoKontrol, like
this one from Kenton
or
... pick some other control surface instead of the Nanokontrol, choose one that has 5-pin MIDI connectors - AFAIK there are no moderately priced ones these days, but you might find something used (Evolution UC-33e comes to mind)