BQ25713: Can it support NiHM?

Typical operation of the BQ25713 is that it is in CC mode until the termination voltage that is set in the "MaxChargeVoltage" register. Once this voltage is reached, the device will enter CV mode at that voltage, which will taper off the current in an exponential decay. This is the typical charging profile for LiIon and similar chemistries. It is not the profile that is generally recommended for NiMH, which is usually CC till around 90% capacity and then trickle charge. Also, the default settings that are selected with the CELL_BATPRESZ pin of 1-4 result in settings that correspond to LiIon cells or similar. I.e. they will set a termination of 4.2V * Cell Number, which is an appropriate number for LiIon chemistries.

This does not mean, however, that the device cannot be used for NiMH. It is possible to use the device with NiMH, but it requires an external microcontroller to drive the current and voltage registers manually to fine tune the termination behavior.

So I would say that the device is really optimized to be easiest to use with LiIon and similar chemistries, but it is possible to use it with NiMH with some manual control by uC to fine tune current and voltage. Basically you have to set proper voltage/current initialization values for your chemistry and then implement the termination profile via uC.