Pour the buttermilk mixture into the bowl of dry ingredients and stir until it is just combined. Add in the diced chile peppers if using.
3 Tablespoons diced chile peppers
Bake the cornbread in the air fryer at 320 degrees F for 20 minutes. The cornbread is done when a toothpick inserted in the center comes out clean.
You can serve from the baking pan or dump the cornbread out on to a wire rack to cool.
Notes
A loaf pan or bundt pan can also work well in the air fryer. Silicone muffin cups would also work for baking corn muffins. Don't use a glass baking dish, it might shatter.
Cooking time will vary depending on the pan you use and your air fryer. I used a 32 ounce round pan in a 5.8 quart Cosori air fryer. My batter was about 1 inch deep in the pan. A smaller pan with deeper batter will take longer to cook. Corn muffins will cook more quickly, in about 10 minutes.