Make the turkey: In a small saucepan, melt butter over medium heat. Add onion and cook until golden, about 10 minutes. Add broth, marmalade, and chipotle pepper. Reduce to a simmer and cook until chipotle-orange sauce is reduced by half, about 20 minutes.
Meanwhile, season turkey with salt and black pepper to taste. In a large nonstick skillet, heat oil over medium heat. Working in batches, cook cutlets until centers are no longer pink, about 2 minutes per side. Transfer to a platter and cover with foil.
In a small bowl, stir 1-tablespoon water into cornstarch. Add to chipotle-orange sauce. Continue cooking, stirring constantly while sauce thickens, 1 to 2 minutes. Add salt and pepper to taste. Pour sauce over turkey cutlets.
Make the couscous: In a medium saucepan, melt butter over medium heat. Add couscous and cook 1 minute, stirring constantly until coated. Add broth and salt and bring to a boil. Reduce heat to low. Cook 5 to 10 minutes or until liquid is absorbed. Add cilantro and more salt and black pepper, to taste. Serve with cutlets.