In a medium saucepan, bring the chicken broth to a low simmer and keep it warm.
Season the chicken breast with a pinch of salt and pepper; in a separate skillet, heat 0.5 tsp olive oil and sear chicken until cooked through, then set aside.
In the same skillet, add the remaining 0.5 tsp olive oil and sauté the onions and mushrooms until the mushrooms are golden and tender.
Stir in the garlic and arborio rice, toasting the grains for 1 minute until the edges are translucent.
Begin adding the warm broth one ladle at a time, stirring constantly and allowing the liquid to be fully absorbed before adding more.
Continue this process for about 18-20 minutes until the rice is creamy and al dente.
Dice the cooked chicken into bite-sized pieces.
Fold the chicken, parmesan cheese, and fresh thyme into the risotto.
Season with the remaining salt and pepper before serving warm.