1) this is a massive undertaking for a minuscule difference that does not bother anyone but a handful of people (or possibly just yourself)
2) things like this are always 600,000 times more difficult than they seem and cost 17 times more than we think they will
3) to do this properly will cost money that will never be recuperated, and it won't be recuperated because... (see #1 and #5)
4) there are already two options for people who like clear lenses, and they are both JDM and bad-ass
5) headlights fabricated by Nissan - a multi-billion dollar corporation - still have issues sometimes with condensation due to a faulty seal...what do you think you'll be able to do that Nissan couldn't?
6) clear lenses on aftermarket headlights available on eBay (for other cars) look like cheap Chinese shit, and they are made by experienced people who work for global corporations