Pour your frozen butternut squash into your air fryer basket and set it to preheat at 400°F (205°C) for 4 minutes. This will get any frost off and break the pieces apart before seasoning, but let them go much longer than 4 minutes and the pieces will start cooking and stick to the basket.
While your frozen squash is heating up, gather your oil, salt, and seasoning of choice (I like ½ cumin & ½ garlic powder). Once the preheating is complete, carefully scoop your warm butternut squash into a small bowl and pat them dry with a dishtowel or several paper towels (this took me about 2 minutes); this is integral to getting them crispy. This is also the best time to cut your pieces into smaller cubes for even cooking. Toss any water left in the bottom of the air fryer after preheating.
Next drizzle the oil, salt, and seasoning over the squash and stir or toss them in the bowl until well-combined (about 30 seconds). If you want to use less oil, spray the inside of your air-fryer basket with a tolerated oil spray; otherwise just proceed to pouring in the pieces.
Arrange the squash in as thin a layer as possible, though a bit of overlap is okay, and then put back the frozen butternut squash in air fryer for another 16 minutes at 400°F (205°C), shaking the basket halfway through (if you tend to forget such things, just set your timer for 8 minutes). Bigger pieces may need an extra 2-3 minutes cooking time. Take out your crispy bits and taste one, then add extra salt (if needed) & enjoy!