the part is rated up to 6.5A when in direct drive (not resisting).
And could you still use the board as a linear resistor?
with limits, as that will increase the heat. But staying in the 10-20% max (drive min = 850) it should be fine. I have made a few modded NB with a double output device for a high power led project and it worked fine.
Note however that when the current increase, it's best practice to have an EXTERNAL resistor. Using the board as a digital resistor for high current is inefficient and will lead to voltage ripple even if the cell is big enough (core voltage won't be regulated if the ripple is too high).
High power LEDs are meant to be current driven with the proper current driver for that reason (and that's why CF and PC are equipped with such a system, which also enhanced battery life and runtime).