M.P.
Sauteed sliced mushrooms would make a good topper or sauce for the chicken. Slice the mushrooms, melt butter and/or olive oil in a skillet. Saute the mushrooms. You can include minced garlic by first sauteing minced/crushed garlic in the oil before adding the mushrooms. You can also add any herbs that you like.
Google chicken with mushrooms and you'll find several recipes.