Heat half of the chicken broth in a medium saucepan. Meanwhile, shred the cheddar cheese and chop the cilantro. When the broth comes to a boil, add the chicken breast. I cut it into several pieces so it cooks faster. Once the chicken is cooked, shred it using two forks or a fork and knife, then set aside. Save the broth in case you need it later.

Preheat the oven to 350°F (180°C). Chop the garlic and melt the butter in a skillet. Once the butter is melted, add the garlic and sauté over medium-high heat until it starts to turn golden. Add the flour and stir for about 30 seconds. Pour in the remaining chicken broth, add the cumin, salt, and pepper. Lower the heat to medium-low. If you have a little leftover broth, you can use it here.

When it starts to boil, add the crème fraîche and green salsa. I recommend adding the salsa gradually until it reaches your preferred level of spiciness. Stir well to combine, then add the cilantro, stir again, and remove from heat.

Pour half of the sauce into a baking dish. Peel and dice the avocado into small pieces. Place some chicken, avocado pieces, and shredded cheese on a tortilla, roll it up, and place it seam-side down in the baking dish over the sauce. Repeat with the remaining tortillas, cover with the rest of the sauce, and sprinkle any remaining cheese on top.

Bake until the top is golden and bubbly. Serve the enchiladas on plates and spoon extra sauce over them.