Wearing gloves peel, deseed and slice or dice the chayote into ¼" thick pieces. (the sap from the squash can irritate some people's skin)
For the Instant Pot:
Place Chayote pieces into your instant pot with 1 cup of water.
Place lid on your pot and put vent into sealing position. Process on manual high for 15 minutes, allow to natural pressure release for 10 minutes and then quick release. Put pot onto saute high, add the additional water, apple cider vinegar, sweetener, apple pie spice and mineral salt. stir to combine.
Continue to cook filling for about 5 minutes, whisk in the xanthan or gluccie until thickened.
Allow to cool slightly and use in any recipe that calls for Apple Pie filling.
For the Stove Top:
Place Chayote slices in 2 cups of water and bring to a boil. Allow slices to become fork tender and remove from water.
In a medium pot add cooked squash (I've used the same pot I boiled the squash in) Add the additional ingredients and cook down until thickened.
Allow to cool slightly and use as you would canned Apple Pie Filling.
Notes
You can also replace the Chayote with Zucchini if it is not available in your area.