In a large Dutch oven, heat 2 teaspoons oil over high heat. Add the sliced onions to the oil and sauté, stirring frequently, until softened and translucent, 3 to 5 minutes.
Stir in the garlic and continue to cook until the garlic is aromatic and the onions are just beginning to color, about 1 minute more. Remove from heat.
Sprinkle the chicken evenly on both sides with three-fourths teaspoon salt and one-fourth teaspoon pepper and place, skin side up and in one layer, over the onions in the Dutch oven.
Add one-fourth cup white wine, cover and bake until the chicken is cooked halfway through, about 45 minutes. Remove from heat.
Remove the par-baked chicken (with the onion-garlic mixture and any liquid) to a separate baking dish or bowl.
To the Dutch oven, add the remaining 2 tablespoons oil and chopped onion and sweat the onions over medium-low heat until softened, 3 to 5 minutes.
Stir in the chopped tomato, tomato sauce, tomato paste and sweet peas, along with the remaining one-half cup white wine, paprika, 1 teaspoon salt, one-fourth teaspoon pepper, chile powder and olives and bring to a boil over high heat.
Reduce the heat to a gentle simmer and add back the chicken, onion-garlic mixture and cooking liquid to the sauce. Cover and continue to simmer until the chicken is cooked through and tender, 15 to 20 minutes.