Bring a large pot of salted water to a boil and cook the brown rice linguine according to package directions until al dente, reserving 2 tablespoons of pasta water before draining.
While the pasta cooks, season the chicken breast with half of the sea salt and black pepper.
Heat the olive oil in a large skillet over medium-high heat and sear the chicken for 5-6 minutes per side until fully cooked, then remove from the pan and slice into thin strips.
In the same skillet, add the sliced cremini mushrooms and sauté for 4-5 minutes until they release their moisture and turn golden brown.
Add the minced garlic to the mushrooms and cook for 1 minute until fragrant.
Return the sliced chicken and cooked linguine to the skillet, adding the reserved pasta water to create a light sauce.
Remove from heat and drizzle with the truffle oil, tossing well to coat all ingredients evenly.
Garnish with grated parmesan cheese, fresh parsley, and the remaining salt and pepper before serving.