All nuts are OK for parrots, even a couple of peanuts (which are not really nuts but legumes) are fine every now and then -more for variety than anything else. Now, as to the comparable nutrition, they are pretty much the same EXCEPT for macadamias being much higher in fat and saturated fat and lower in omega 3 so, in reality, walnuts are much better than macadamias. I always have, at least, 3 if not 4 different kinds of nuts and kind of switch what I give them but walnuts are always served because they are highest in omega 3 and have the lowest omega 3 to 6 ratio.
Below, two charts on nut nutrition comparison:
https://www.thespruceeats.com/nut-nutri ... rt-1328752https://vegfaqs.com/omega-3-to-6-fat-ratio-nuts/