Q. Can I install NS200 rim, brake and front suspension set on NS160? If I can then what will be cost and problems?

Yes you can do that but why? You could've just bought ns 200. This upgrade will cost you a lot. The front and rear rim will cost around 9k and front suspension will cost you 8.5k the front brake callipers and disc will cost 3.7kIn total that's 22k. If you plan on installing rear disc too then add another 3k . Also the rear sprocket of ns 160 won't fit on ns 200 rim without some modification, because the ns 200 Rim has 6 grooves om the hub to fit the sprocket, but the ns 160 sprocket only has 4 grooves. So it won't fit unless you do something about the extra gaps.

I am not sure as ns 200 & 160 has different chaccy tuning. Also the rear swingarm is different so it will be a task to make these changes

No