Bring a large pot of salted water to a boil and cook the chickpea tagliatelle according to package directions until al dente.
While the pasta cooks, season the chicken breast with half of the sea salt and black pepper.
Heat a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until golden and cooked through, then set aside to rest before slicing.
In the same skillet, melt the ghee and add the sliced cremini mushrooms, sautéing until they release their moisture and become deeply browned.
Add the minced shallot and garlic to the mushrooms, cooking for 1-2 minutes until fragrant and softened.
Drain the pasta, reserving a small amount of pasta water, and add the noodles directly into the skillet with the mushrooms.
Toss the pasta with the sliced chicken, truffle oil, parmesan cheese, thyme, and remaining salt and pepper, adding a splash of pasta water if needed for a silky finish.