Honestly, the thing doesn't even need a heatsink.
It's rated to operate at up to 109C and only puts out 4.5W of heat at maximum load, with more typical power consumption/dissipation in the 2-3W range. The motherboard PCB itself will provide all the cooling it needs the overwhelming majority of the time and most heatsinks attached to it on most boards are either redundant, or are actually extra cooling for the IOH/MCH, not the SB itself.
-- page 10, for reference.
If you want some extra peace of mind, the adhesive heatsinks you mention should be plenty.