Preheat the oven to 400 degrees Fahrenheit.
Cut the spaghetti squash crosswise and scoop out the seeds and pulp. Spray the inside with avocado oil and season with garlic powder, salt and pepper. Season the chicken with the same spices.
Place the squash cut-side down on a parchment-lined baking sheet with 2–3 garlic cloves underneath each half. Roast for 30–35 minutes, or until the strands easily pull away with a fork but are still slightly al dente.
While the squash cooks, prepare the chicken using your preferred method. I like to air fry the chicken while the squash is in the oven.
Once the squash is done, turn the halves on their sides and let them rest for 10–20 minutes so excess steam can escape.
Add the cottage cheese, ¼ cup chicken broth and roasted garlic cloves to a blender. Blend until completely smooth.
If using onion, sauté it in a large skillet over medium heat for 4–5 minutes, or until softened. Reduce the heat to low. If the skillet is very hot, let it cool for a minute before adding the cottage cheese mixture.
Pour the blended cottage cheese sauce into the skillet. Add the peas and warm gently over low heat for 2–3 minutes, stirring frequently. Do not let the sauce simmer or boil.
Stir in most of the Parmesan cheese and continue cooking just until the cheese is melted and the sauce is warmed through. Season with salt, pepper, garlic powder and Italian seasoning to taste.
Use a fork to scrape the spaghetti squash into strands. Add the squash to the skillet and gently toss with the sauce.
Slice the cooked chicken and add it to the skillet or serve it on top of each bowl. Garnish with the remaining Parmesan cheese.
If the sauce is too thick, add a small splash of chicken broth. If it is thinner than you prefer, add a little more Parmesan cheese.