Place the cubed chicken, sliced carrots, celery and frozen peas in a large pan and cover with salted water. Bring to a boil and cook until the veggies are fork tender and the chicken is no longer pink inside, about 7-9 minutes. Drain and cover to keep warm. Set aside.
While the chicken cooks, melt the butter in a large sauce pan over medium/high heat. Add in the onions and cook until golden brown, about 1 minute. Add in the almond flour and coconut flour and cook, stirring constantly, until golden brown and the flour begins to absorb the butter, just 1 minute or so.
Stir 1 cup of the chicken broth, along with the celery seed, into the flour mixture. Bring the mixture to a boil and then turn the heat down to medium and simmer, stirring occasionally, until the sauce thickens and reduces by about half, about 9-10 minutes.
While the sauce thickens, heat the olive oil in a large pan over medium high heat.
Spiralize the potato using the 3mm blade and place it into the olive oil. Cook until the noodles wilt and turn golden brown, about 10-12 minutes, stirring occasionally. Season with a pinch of salt.
Once the sauce has thickened, turn the heat down to medium low. In a separate, medium bowl, whisk together the Greek yogurt and the remaining 1 1/2 Tbsp Chicken broth until smooth and creamy. While whisking, pour into the chicken broth mixture and stir until well combined. Bring the mixture to a simmer and cook until it begins to thicken, about 5 minutes. Season to taste with salt and pepper. *
Place the cooked potato noodles into the sauce and stir until evenly coated. Divide between plates, top with the chicken/vegetable mixture and garnish with fresh parsley.
* When cooking with Greek yogurt it can slightly separate and look a little granular. This is normal and does not affect the taste. However, because of these, you do need to eat this dish immediately or it becomes dry.