Pound out each chicken breast with a mallet, rolling pin, or skillet, until about ¼ inch thick all over. Season each side of the chicken with salt and pepper.
Prep mushrooms and sundried tomatoes, as mentioned in the ingredient list.
Heat a few tablespoons olive oil in a skillet over medium heat.
Add chicken to the hot skillet and cook until just browned, about 3-5 minutes each side. Remove from pan and set aside.
Add mushrooms and sundried tomatoes to the skillet and cook for 4-5 minutes, or until browned.
Pour sauce mixture into the pan with the vegetables and bring to a simmer. Cook for another 4-6 minutes, or until sauce starts to thicken.
Add chicken back to skillet and cook for an additional 4-6 minutes, or until cooked through.
Remove from heat and serve with a lemon wedge.