Wash, peel, core and dice the chayote squash. Heat a pot or large skillet to low and melt the butter. Add in the squash and toss to coat. Cover with a lid and cook for 10 minutes.
Preheat oven to 350F. Add in the rest of the filling ingredients and stir to combine. I prefer using this silicone spoon, so nothing sticks to it! Continue cooking for 10 more minutes, covered or until fork tender. Before moving onto the next step, taste the filling mixture for sweetness. If you want it sweeter, add in more Swerve confectioners at this time.
Add the almond flour, pecans, apple pie spice and Swerve into a mixing bowl and mix them together. Then pour the melted butter over the top and mix until well combined. Once you add the butter, you’ll see the crumbles will start to form.
Place on the lower ⅓ rack of your oven and bake for 30-35 minutes or until the topping is slightly golden. If the crumble topping starts getting too dark, tent it with foil and continue baking. Store leftovers in the fridge in an airtight container for several days or freeze.