Heat a large pot over medium heat and add olive oil. Add the chicken and cover, cooking until golden brown, tossing once or twice during cook time, about 10 minutes. Reduce the heat to low and remove the chicken with a slotted spoon, placing it in a bowl. Add the shallot, garlic and mushrooms, stirring well. Cover and cook until the mushrooms soften, about 5 to 6 minutes.