Boil water and cook chickpea pasta according to package directions, reserving 2 tablespoons of pasta water before draining.
Season chicken breast with half the salt and pepper, then pan-sear in a non-stick skillet over medium-high heat until cooked through, about 5-6 minutes per side.
Remove chicken from the pan to rest, then slice into thin strips.
In the same skillet, add the sliced mushrooms and cook until browned and tender.
Add minced garlic to the mushrooms and sauté for 30 seconds until fragrant.
Deglaze the pan with chicken broth, scraping up any browned bits, and simmer for 2 minutes to reduce slightly.
Reduce heat to low, then stir in the Greek yogurt, Parmesan cheese, remaining salt, pepper, and the reserved pasta water to create a smooth sauce.
Toss the cooked pasta and sliced chicken into the sauce until well coated.
Remove from heat and drizzle with truffle oil and fresh parsley before serving.