Add butter to a large skillet, saute onions, garlic and mushrooms until the onions become translucent, about 5-7 minutes. Add flour and cook, stirring, for 1 minute. Whisk in the chicken broth and the cream. Simmer over medium low heat until it thickens. Add chicken, chives, wine, salt and pepper. Stir to combine. Remove from the heat and let cool for 10 minutes before rolling into the crepes.