Fun question!

The short answer is yes, maybe, but…
the flavor may change significantly. Many vegans lacto ferment ground up nuts in order to make a vegan cheese similar looking to feta. The process is actually pretty interesting and maybe some that are casein sensitive out there might be interested in this process. Here are a couple of helpful tutorials:

How to make lacto fermented nut cheese

http://www.nathalielawhead.com/candybox/lacto-fermentation-raw-vegan-cheese-making-and-more

http://craftypantscarol.blogspot.com/2011/02/aged-fermented-nut-cheese-everything.html

If you just throw some whey in your nut butter, you’re basically making this cheese stuff (minus the coconut butter they call for). You’re likely going to end up with a quasi “cheese” spread instead of a nutty butter.

Now, lacto fermenting the nuts before dehydrating them into crispy nuts? That, I think, may work better! Throw some whey into the soak water (watch out for sliminess), rinse, dehydrate and grind as usual. Again, I’m not sure about the flavor, but I think the results would be a little better this way. It may still turn out cheesy.

Soaking in warm water (salt optional) is plenty sufficient for reducing phytic acid in nuts.