Many species that are found naturally in soft water can survive in hard water. Where many issues arise is in coloration and sexual activity in these specimens. Their colors often appear washed out, and any activity that does occur ends badly as low Ph, soft water inhibits most bacteria and fungus. Those eggs laid in hard water tanks fall victim to contagions and symptoms that these fish never evolved for. Choosing fish with a similar water chemistry is a good idea, but can be difficult in smaller nano tanks. Some that I would recommend would be Psuedomugils, Dwarf Livebearers, Desert gobies and some Stiphodens, danios and look into Celestial Pearl Danios or the Emerald Rasbora. There are a variety of Killifish that are an option and even Ricefish could work if the tank size is appropriate. Neocaridina shrimp do well, as do some Sulawesi shrimp with a high enough temperature. There are a lot of options, but it will take a bit more searching. They can be far more fulfilling to keep as they are comfortable and exhibit more relaxed behavior.
"In the land of the blind, the one-eyed man is king" Desiderius Erasmus