Black Walnut Wood Chips?

I have several fruit trees that I mulched primarily with “green mulch.” I would just mow the lawn and throw the grass clippings on top. Has worked good but decomposes fairly quickly and needs to be done pretty much every year.

I now have access to some wood mulch that is almost all black walnut. I’m thinking of using this going forward but I’ve heard conflicting information about it. Is it safe to use or will it hinder the growth of my trees?

Anyone with experience who would like to share their thoughts would be greatly appreciated?