We tow 172s and 182s by the nosewheel, with a powerful little tractor, sometimes through a few inches of snow and uphill. The nosegear can take it. HOWEVER: You can damage stuff by slamming the tractor into the towbar (or vice versa) which is why my towing setup has rubber dampers built into it. You can also oversteer the nosewheel and break the stop collar. Never force the steering with the towbar. If it won't turn any further with normal hand pressure, stop turning it. Get someone to hold the towbar while you get down under that thing and have a look at what's happening when the helper turns the nosewheel; you'll see the stop collar and lugs. And you might notice how lightly built the torque links are ("scissors") and understand that you can break those, too, by forcing the steering.