Preheat the oven to 350°F.
I like to use my cast iron skillet for this. If you don't have one you'll need some kind of oven safe pot. Heat up the skillet over medium high heat until you just start to see a little smoke rising. Then add in 3 tbsp of olive oil. Move the oil around and coat the skillet.
Pat down the chicken with a paper towel, cut into smaller sections so you have around 6-8 portions. Then season it with salt and pepper. Don't be afraid to use a good amount of salt here. Chicken breast need help.
Lay the chicken pieces in the skillet and sear on both sides for around 2 minutes each. You should hear them sizzling. Once done, remove them from the pan onto a plate.
With the same skillet, add in the rest of the olive oil and saute onions until soft and see through. Add garlic and cook for 30-60 seconds. Don't burn the garlic. Then the chicken broth, crushed tomatoes, wine, brown sugar, and salt. Stir and bring to a boil. Then add the chicken back into the skillet. Try to make sure the chicken is almost all the way submerged in the sauce.
Bake in the oven for 40-50 minutes
Serve the chicken hot with rice and some asparagus. I think both would go well.