Preheat oven to 425 degrees.
Season chicken well with salt and pepper.
Add oil to a large skillet over medium heat. Add chicken tenders to heated oil. Cook covered until chicken is cooked through, about 10-15 minutes. Remove chicken from pan and set aside.
Add butter to the pan and melt over medium heat. Use a whisk to scrape up the bits in the pan from the chicken.
Whisk flour and bouillon into the melted butter. Cook and whisk for 30 seconds.
Add half & half and stir until mixture is thickened, it’s okay if it’s a little lumpy. Remove from heat.
Whisk in sour cream, green chiles, cumin, garlic powder, and onion powder. Add 2 cups grated cheese and stir together.
Set aside 1 ¼ cups of the mixture to use for the topping.
Dice the cooked chicken. Stir it into the mixture in the pan.
Spray a 9x13 inch baking dish with cooking spray.
Add a heaping ½ cup of the chicken mixture to a tortilla and roll it up. Place it in the dish. Continue with the rest of the mixture and tortillas.
Spread the reserved topping over the enchiladas. Sprinkle the top with 1 cup grated cheese.
Bake uncovered for 30-45 minutes or until warmed through and the cheese is melted on top. Cover with foil if needed if cheese begins to brown too quickly. Serve warm.
