I run Shinko 705's on my Wee Strom. really like them on that bike. Not sure if they make the correct size for the NT. 705's are relatively inexpensive and the rear lasts about 7 to 8k miles on my Wee. I get two rears to every front.
Just my two cents worth. The NT has too much plastic to be riding it in places where you would need to have duel sport tires, on a regular bases. Once in a while OK but the roughness of the dirt roads would evidently be hard on the plastic.
Best to get an inexpensive Wee650 for that kind of riding. Set up properly, the V Strom 650 is a bullet prove bike That does it all. Pavement, Dirt, City, Country. Long distance, short around the block rides. JMO.