right this is where it gets complicated :-)
There are possibly hundreds of types and formulations of 'nylon'.

I have found 2 that work reasonably well in an unenclosed printer.
MyMat nylon from spain and taulman 645 https://taulman3d.com/645-features.html
http://www.mymatsolutions.com/

Every other nylon I have tried has been an abject failure.
Hell every other taulman filament I've tried has been impossible to use outside a heated enclosure.
But nylon 645, is pretty good.

So while the heated enclosure would help - it's not strictly necessary with the right material.
And yes, the hairdryer and enclosure should work quite well.
Throw in a thermostatically controlled switch for the dryer and you've got a temperature controlled build volume :-)

Obviously everything else inside the volume is getting heated, so that can throw up issues if you have it too hot - so personally I'd always go the thermostat route.