Warm the chicken broth in a small saucepan over low heat and keep it at a bare simmer.
Heat the olive oil in a wide skillet over medium heat and add the diced chicken breast, seasoning with half of the salt and pepper.
Cook the chicken until golden and cooked through, then remove it from the pan and set aside.
In the same pan, add the sliced mushrooms and shallots, sautéing until the mushrooms have released their moisture and turned deep brown.
Stir in the minced garlic and arborio rice, toasting the grains for 1-2 minutes until the edges of the rice become translucent.
Add the warm chicken broth one ladle at a time, stirring frequently and allowing the liquid to be fully absorbed before adding the next ladle.
Continue this process for about 18-20 minutes until the rice is tender but still has a slight bite (al dente).
Fold the cooked chicken back into the pan along with the fresh thyme, remaining salt, and pepper.
Remove from heat and stir in the grated parmesan cheese until the risotto is creamy and well-combined.
Serve immediately in a warm bowl.