I have used pecan shells in my wood burner. They are easy to come by in my area. They are excellent. I have just gotten a pellet smoker so these are on my list to try. I would suggest a 50-50 blend of hickory and these pecan shell pellets.
@deanscharphorn6035 Texas style brisket is fat side up, but there is nothing wrong with smoking fat down. Experiment, have fun with it, and then decide what version works best for you.