Pat the chicken thighs dry with paper towels. Cut them into approximately 1-inch pieces. In a bowl, toss the chicken pieces with salt, black pepper, and garlic powder until evenly coated.

Heat 1 tablespoon of olive oil in a large skillet or Dutch oven over medium-high heat. Add the seasoned chicken pieces in a single layer, working in batches if necessary to avoid overcrowding. Sear for 3-4 minutes per side, until browned and cooked through. Remove the chicken from the skillet and set aside.

Reduce the heat to medium. Add the diced yellow onion to the same skillet and cook for 3-4 minutes until softened, scraping up any browned bits from the bottom of the pan. Add the minced garlic and jalapeños, and cook for another 1-2 minutes until fragrant.

Stir in the diced peaches, apple cider vinegar, soy sauce, brown sugar, and grated ginger (if using). Pour in the chicken broth. Bring the mixture to a gentle simmer, stirring occasionally, and cook for 5-7 minutes to allow the flavors to meld and the peaches to soften slightly.

In a small bowl, whisk together the cornstarch and cold water until smooth to create a slurry. Slowly pour the cornstarch slurry into the simmering sauce, whisking continuously. Continue to cook for 1-2 minutes, stirring, until the sauce thickens to your desired consistency.

Return the cooked chicken pieces to the skillet with the sauce. Toss gently to coat the chicken thoroughly. Heat through for 1-2 minutes until the chicken is warmed.

Serve immediately over rice, quinoa, or with a side of steamed vegetables. Garnish with fresh chopped cilantro and chopped roasted peanuts, if desired.