In this paper we propose a rapid and continuous method for deposition of porous nanocrystalline coatings for functional applications. The Solution Precursor Plasma Spraying technique was used to fabricate porous nanocrystalline SnO₂ coatings for gas sensor applications. Experiments following two statistical designs were implemented to screen and investigate the spraying parameters’ effects on coating crystallinity and porosity to gain a better understanding of this technique. The spraying stand-off distance, solution flow rate and gun current were identified as having significant effects on porosity. The investigation yielded a microstructure comprised of nano-sized particles agglomerating into porous spheres with interconnected channels between the spheres. A deposition mechanism was postulated to explain this microstructure.  The porous coatings had ethanol sensitivities at room temperature comparable to those reported in the literature for conventional thick-film coatings and a maximum sensitivity near 200ºC.