Preheat oven to 350 degrees.
Break up the tofu and place it into a food processor with the regular metal blade. Run the processor for around a minute until the tofu is broken down.
Add all of the remaining ingredients and let the food processor run for a couple of minutes until the mixture forms a dough.
Knead the dough with your hands for about a minute, forming a large rectangle, about 12 inches by 8 inches.
Using any cookie cutter shape you like, cut shapes from the dough.
Line a baking sheet with parchment paper or foil, spray with oil, and evenly space out the seitan chicken pieces.
Cover the pan tightly with foil and bake for 20 minutes.
Remove the foil and allow the nuggets to cool, then transfer to a bowl or container and refrigerate for at least 3 hours.
Prepare the coating by whisking the vegan yogurt or sour cream with the plant milk in a bowl.
In another bowl, mix the bread crumbs, starch, flour, and seasoning.
Dip the nuggets in the wet mixture, then into the dry mixture, pressing the coating into both sides.
For air frying, place nuggets in a single layer in the air fryer and cook at 375 degrees for about 10-12 minutes.
For oven baking, preheat oven to 400 degrees, place nuggets on a baking sheet, spray the tops, and bake for about 10 minutes, flipping halfway.
