Bring a large pot of salted water to a boil and cook the chickpea tagliatelle according to package directions until al dente, reserving 0.25 cup of pasta water.
While the pasta cooks, heat the olive oil in a large skillet over medium-high heat.
Season the sliced chicken breast with half of the sea salt and black pepper, then sauté until golden and cooked through, about 5-6 minutes.
Remove the chicken from the skillet and set aside; in the same pan, add the sliced mushrooms and shallots, sautéing until the mushrooms are browned and tender.
Add the minced garlic to the mushrooms and cook for 1 minute until fragrant.
Return the chicken to the skillet and add the cooked tagliatelle, reserved pasta water, and truffle oil.
Toss everything together over low heat until the sauce coats the pasta evenly.
Serve immediately topped with grated parmesan cheese, fresh parsley, and the remaining salt and pepper.