It wasn't my original recipe, but I have tried it with variations and they are all flavor popping. I would think it would not matter, as long as you use a healthy oil, even olive, sesame, or coconut. Grapeseed oil and flaxseed oil are both light tasting oils and I think olive oil is a little stronger tasting. But with the garlic and cilantro, you won't taste the difference.
Try the recipe - you will love it. I like the taste of the brazil nuts not too finely ground, don't know why.