Heat a regular large skillet over medium-high heat {don't use a non-stick pan if possible} and add oil.
Season chicken with salt and pepper. Cook chicken in hot skillet until done, about 5-7 minutes per side depending on thickness. Remove chicken from skillet and set aside [cover with foil to keep warm].
Turn the heat to medium and add the mushrooms. Cook until they release their juices, about 7 minutes. Add garlic and cook for 30 seconds, constantly stirring.
Add chicken broth and wine (if using), and scrape all the browned bits off the bottom of the pan. Allow liquid to boil and reduce by about half, about 5 minutes. Be sure to make sure it's not burning and stir occasionally.
Once the sauce has reduced by about half and is to your desired consistency, turn off heat and stir in the lemon juice.