Preheat the oven to 350°F (175°C).
Heat a large oven-safe skillet over medium heat and add the olive oil.
Whisk in the flour and cook, stirring, until golden brown, about 2 minutes to make a roux.
Slowly whisk in the chicken stock, tomato sauce, and tomato paste until smooth.
Add the diced chipotle pepper, adobo sauce, chili powder, cumin, onion powder, garlic powder, smoked paprika, cayenne, salt, and pepper; whisk to combine and bring to a simmer.
Reduce heat to low and simmer for 5 minutes, then remove from heat.
Scoop out 1/2 cup of the sauce and set it aside for mixing with the chicken (reserve more for topping if you like).
In a large bowl, combine the shredded chicken, chipotle chili powder, sliced green onions, enchilada sauce, and the reserved 1/2 cup sauce; mix well. Stir in 1/2 cup of the grated cheese.
Spoon 2 to 3 tablespoons of the chicken mixture into the center of each tortilla, roll tightly, and arrange seam-side down in the skillet on top of the remaining sauce.
Spoon additional sauce from the skillet over the tops of the rolled enchiladas to cover them, then sprinkle with the remaining cheese.
Bake in the preheated oven until cheese is golden and bubbly, 20 to 25 minutes.
Remove from oven and let rest briefly before serving; top with extra green onions or cilantro if desired.
