That depends on the design of the case, but all of our wireless chargers are compatible with all of our Clic cases.
If your non-Native Union case is simply a protective case, as long as its back panel is no thicker than 3mm, wireless charging should work fine. However, if the back panel is thicker, or if the case contains a battery, magnet, or other metal, it may prevent the phone from charging wirelessly.
Please note that, with a case, the placement area will be smaller, and the phone needs to be more carefully centered on the charging area for successful charging. Charging through cases performs better with a QC/PD charger, when compared to a simple 5V or 10V charger.