Atmospheric Nitrogen exists as N2 (of course it's a triple bond between the N atoms. Preparing HNO3 entails oxidation of N from 0 to +5. While it is possible to oxidize atmospheric Nitrogen from 0 to +2 in NO by electric sparking, it will probably require a series of steps before you get Nitrogen at +5 oxidation state and the temperatures required will be extremely high and uneconomical