In a shallow dish, combine flour and seasoning. Coat each piece of chicken in the flour mixture.
Heat skillet on medium-high heat. Add oil and sear each piece of chicken on both sides until slightly browned, approximately 1 minute per side. Place in a baking dish and set aside.
Prepare the sauce in the same pan. Lower heat to medium. Add oil and onions.
Scrape up all the stuck-on bits on the bottom of the pan as you sauté the onions. Cook until soft and golden, stirring frequently. This will take about 20 minutes. Don’t rush this process, you want soft, golden, caramelized onions.
Once the onions are caramelized, Add seasoning, garlic, soup mix, soy sauce, and wine and stir to combine. Cook for 15-20 minutes, stirring frequently. At this point you can preheat the oven to 350℉.