Current Sensing Design
For almost any normal design, that bias current is so low it means "stop worrying, have a nice weekend".

The design consideration is that when you put 100nA into your current sensing network from that pin, that the voltage rise is insignificant compared to the \$\pm\$50mV of uncertainty in the current limit threshold voltage of the chip.  That means that in a normal design your current sense resistor should be no more than 500k\$\Omega\$ -- which, since most current sense resistors are in the milliohm range, should be a pretty easy condition to satisfy.