Hi Mark:
Yes, Forrest Keeling is a quality nursery with many hardmast species to choose from: oak, hickory, walnut, chestnut, etc.
When direct seeding black walnuts, my typical go-to method for planting a minimal number of walnuts is to simply plant one nut per hole, no deeper than 3 inches (2 inches is just fine). Don't add compost or fertilizer to the planting hole.
Best of luck!