Bring a large pot of water to a boil. Add the pasta to the boiling water and cook until just done, about 5-6 minutes. Drain the pasta and set aside.
Place a large skillet over medium to high heat and swirl in the avocado oil. When the oil begins to shimmer, add the garlic and leeks, and season with salt and pepper. Cook, stirring frequently, until the leeks become transparent.
Add the chicken, season with salt and pepper, and cook for about 4 minutes, until the chicken is almost done. Add the mushrooms and thyme. Cook, stirring frequently, for 4-5 minutes, or until the mushrooms have released their moisture. Slowly stir in the coconut milk, followed by the nutritional yeast.
Add the pasta and stir. Taste and adjust the seasonings.
Serve. Enjoy!