I would make a sort of vaguely North African tagine out of the squash, potatoes, chicken juice, and harissa. If it were me, I'd also add a can of chickpeas, because that's the way I roll, and some spices like cumin and cinnamon. Oh and an onion.

Let me break it down:

Saute a diced onion in a little chicken fat. Add diced squash, potatoes, chickpeas, spices, harissa, and whatever non-fat parts of the chicken drippings you have. You'll also want some extra liquid... at minimum, some water, or perhaps some canned tomato puree or some stock or a combination of them. Simmer on the stovetop til the squash and potatoes are soft enough.

I'd serve that over rice with a dollop of yoghurt, and a green salad on the side.