Combine the vital wheat gluten, chickpeas, nutritional yeast, garlic powder, onion powder, smoked paprika and vegetable broth in the bowl of a food processor. Pulse until the mixture forms a dough.
Knead the dough for a few minutes. Roll it into a log and cut off ½ inch pieces. Flatten them out with your hand, and set aside until all the nuggets are made.
Preheat the oven to 425° F (220° C). Line a baking tray with parchment paper.
Drop the nuggets into the boiling water and boil for 15 minutes. Be sure to drop them all in the water at the same time so that they cook evenly. Remove them from the water with a slotted spoon and transfer to a clean plate.
Prepare your dredging station. Combine the flour, garlic powder, onion powder, smoked paprika and vegan buttermilk in a large bowl. If the batter is too thick, add a bit more milk. Put your breadcrumbs in a separate shallow bowl.
Dredge the seitan nuggets in the batter, followed by the breadcrumbs. Lay them out evenly on the baking tray, brush with olive oil and bake for 25-30 minutes, turning one half way through.
Mix the vegan mayo and chipotle sauce together. Serve the nuggets hot out of the oven with the chipotle sauce.