Preheat your oven to 400°F and season the chicken breast with half of the sea salt and black pepper.
Place the chicken on a baking sheet and roast for 20 minutes or until the internal temperature reaches 165°F, then slice into strips.
In a small saucepan, bring the chicken broth to a very low simmer and keep it warm throughout the cooking process.
Heat the olive oil in a large skillet over medium heat, then add the diced onion and sliced mushrooms.
Sauté the vegetables for 5-7 minutes until the mushrooms have released their moisture and turned golden brown.
Add the minced garlic and Arborio rice to the skillet, stirring for 2 minutes to lightly toast the grains.
Add the warm broth to the rice one ladle at a time, stirring constantly and waiting for the liquid to be absorbed before adding the next ladle.
Continue this process for 18-20 minutes until the rice is creamy and tender but still has a slight bite.
Stir in the parmesan cheese, fresh thyme, and the remaining salt and pepper.
Divide the risotto into a bowl and top with the sliced roasted chicken breast.