Add the chicken bones, Anaheim pepper, carrots, celery, ginger, peppercorns, Celtic salt, lemon (halved), garlic cloves, and onion (quartered) to a 6qt or 8qt Instant Pot. Fill with enough water to cover the ingredients but do not exceed the maximum fill line.

Secure the lid on the Instant Pot, ensuring the sealing valve is closed. Select the "Manual" or "Pressure Cook" setting and adjust the time to cook on high pressure for 100 minutes.

Once the cooking time is complete, allow the Instant Pot to release steam naturally. This step is crucial for safety and ensures that the flavors continue to develop as the pressure decreases.

After the pressure has fully released and the valve has dropped, carefully open the lid. Use a stainless steel funnel lined with a mesh strainer to pour the stock into mason jars. Make sure to strain out all solid ingredients.