Slice each large chicken breast in half horizontally to make 4 fillets, or use 5–6 boneless thighs; cover with plastic wrap and pound to even thickness if needed, then pat dry.
In a shallow dish, whisk together the 2 tablespoons flour with paprika, garlic powder, onion powder, ground cumin, salt, pepper, and chipotle; set aside 1 tablespoon of this mixture for the sauce.
Dredge each piece of chicken in the remaining flour-spice mixture, shaking off excess, and place on a dry surface.
Heat 2 tablespoons butter and 2 tablespoons olive oil in a large skillet over medium-high heat until hot.
Add the chicken and cook 4–5 minutes per side (adjust for thickness) until golden and cooked through; transfer chicken to a plate but leave pan drippings in the skillet.
Whisk the chicken broth and cornstarch together in a small bowl until smooth.
Add the broth-cornstarch mixture to the skillet, then stir in the brown sugar, soy sauce, lemon juice, Dijon mustard, reserved 1 tablespoon flour-spice mixture, dried parsley, thyme, oregano, and a dash of red pepper flakes.
Bring the sauce to a simmer, scraping up browned bits from the pan, and cook until it thickens to your liking, stirring often; taste and add more lemon juice if you prefer less sweetness.
Return the chicken to the skillet, spoon sauce over the pieces, and warm over low heat until the chicken is heated through and glazed with sauce.
Serve warm with mashed potatoes, polenta, rice, or cauliflower rice, and garnish with fresh parsley if desired.
