Preheat oven to 400 degrees. Spray a medium baking dish with avocado oil.
To make the “noodles,” slice two sides of the zucchini lengthwise, creating flat sides. Use a vegetable peeler to slice each zucchini into flat strips.
Lay the zucchini slices on paper towels. Liberally salt the surface and allow to sit for at least 20 minutes. Used paper towels to blot away the excess moisture.
Make the filling by combining chicken, ricotta, Parmesan, egg, Italian seasoning, salt and pepper in a medium bowl. Stir until combined
Lay two strips of zucchini noodles side by side, so that they overlap lengthwise. Do the same with two more noodles on top, perpendicular to the first strips.
Add about a tablespoon of filling to the center of the zucchini. Working one side at a time, bring the ends of the strips together to fold over the center.
Turn the ravioli over and place in a baking dish seam-side down.
Pour sauce over ravioli and top with Gruyere cheese. Bake for 20 minutes.