The invention provides certain nicotine salts, co-crystals, and salt co-crystals and provides novel polymorphic forms of certain nicotine salts. In particular, nicotine salts with orotic acid are described. The invention further provides methods of preparation and characterization of such nicotine salts. In addition, tobacco products, including smoking articles, smokeless tobacco products, and electronic smoking articles comprising nicotine salts, co-crystals, and/or salt co-crystals are also provided.