Melt 1 tablespoon butter in a medium skillet. Add mushrooms; cook until soft. Transfer to a small bowl; cover.
Whisk flour, garlic powder, salt, and black pepper together in a shallow dish or bowl. Dredge chicken in flour mixture; shake off excess.
Cook bacon in same skillet over low heat until cooked but not crisp. Melt 2 tablespoons butter in skillet. Add chicken; cook over medium heat for 2 minutes per side, adding remaining 1 tablespoon butter as needed to prevent burning.
Transfer chicken to a plate; cover and keep warm. Slowly add water to cornstarch in a medium bowl; whisk together, then whisk in wine. Add to skillet with reserved mushrooms; heat until sauce begins to boil and thickens. Top chicken with sauce; serve.
