Preheat the oven to 375 degrees.
Heat a cast iron skillet over medium high heat and add the chicken pieces. Sprinkle the chicken lightly with salt and pepper, then cook until the pieces are cooked through.
Turn off the heat and, using two forks, shred the chicken in the pan. Return to medium heat and add the fire roasted green chilis, grated zucchini, chopped cilantro, and three-quarters of the bottle of salsa verde. Mix well and cook for another 5 minutes or so.
Prep for rolling the enchiladas by setting out your baking dish and a cutting board. Dump the enchilada sauce into another pan or deep plate, and have the chicken and tortillas close by.
Dip each tortilla into the enchilada sauce, then add 2-3 spoonfuls of filling, about 3-4 tablespoons each. Sprinkle shredded cheese on top of the filling, roll the tortilla up tightly, and set each enchilada in the baking dish.
Spoon the leftover enchilada sauce over the enchiladas, then sprinkle the tops with more shredded cheese. Bake at 375 for about 15 minutes, until the cheese is melted and the sauce is bubbling.
Sprinkle with crumbled queso fresco, chopped cilantro, and pepitas, and serve immediately.
