As long as the charger can supply at least the amount of current the phone needs, you're fine. (I used to charge phones from a 30 Amp bench supply in the store.)
It's the voltage that matters - 5 Volts. (If it's fast charging, like the X4, the charger has to be the same kind of fast charging [there are 3 at the moment], or the phone will slow charge. But it won't damage anything.)