3 NiMHs lack the voltage to power an XM-L2, maybe an XM-L, but it's not the amperage, it's the voltage. Eneloops will flat out do 10 amps, but not if the voltage isn't there for the increased voltage the led needs, as amperage increases.
Any more, I prefer 4x NiMHs for most Cree and Nichia leds over 3 amps. 3X is fine for low amperage jobs, 3 amps or less.